The partial solar eclipse taking place on March 20th left me wondering if there is any record of past events for this area.
Luke Howard‘s The Climate of London describes a similar such event that took place on September 7th, 1820. Howard describes how the thermometer fell from 68.5°F to 62.5°F. After making observations at his home in Tottenham at 10.30am Howard made his way to Stoke Newington to visit fellow scientist and Quaker, William Allen, to observe and record the eclipse.
From his account it appears that, though the weather was settled, there was a fair bit of cirrocumulus drifting across the sun during the eclipse.
As well as the fall in temperature Howard’s account describes the strange light: “The sunshine against the house was so dim as to be quite striking; and the view before us to south, which included the nearer parts of London, showed much the same as afterwards at six In the evening – dusky but not dark.”
Howard noted that the lowest temperature was observed about seven minutes after the greatest obscuration. He also mentions that his son noticed that spots of light falling through the shade of trees were in the shape of crescents, mirroring the lunar disc across the sun, rather than globular. He also states that Venus was very easily visible during the eclipse.
Though Howard’s account is by no means groundbreaking, it would be another hundred years before another eclipse proved Einstein’s theory of general relativity, it is fascinating how we are still just as fascinated by the sun as our forbears were.
I was in southern Turkey for the last solar eclipse which I believe was overcast in the London area. I had some data from my then AWS but I’ve misplaced it. That Oregon unit didn’t have the means of recording every minute.
Though I was outside the area of totality I still experienced the classic eclipse effects: the birds singing before going silent, reduced warmth of the sun and a very strange and eerie ‘blue’ light that is cast over everything. I’ve not experienced anything like it since and only hope that the sky on March 20th is a bit clearer than it was 16 years ago.
It is impossible to know what the weather will be like on the day at this range though a look back through my records to 1981 reveals that weather conditions on March 20th, the Vernal equinox this year, can vary greatly. In 2003 a high of 17.5C was recorded with 6.9 hrs of sunshine. However, two years earlier, the temperature reached just 4C as 8.2mm of rain fell.
It seems the media is working itself up into a frenzy over the eclipse, talking up the possibility that the event will cause a power surge that could interrupt supplies across Europe. However, the fact that solar accounts for just 10% of Europe’s renewable energy would suggest that such hyperbole is similar to the hysteria over the Y2K ‘Millennium Bug’ that failed to materialise?
* I will be revisiting this blog after the eclipse has happened to post results from my AWS readings.
** There’s a full account of Luke Howard’s eclipse here
The weather model GFS (Global Forecasting System) has, for years, teased weather anoraks with mouthwatering possibilities of what the weather could be like 5 to 10 days away. Many ‘coldies’, that unexplained breed of weather anorak whom lust after extreme cold and snow every winter, often look at the end of the run, out to 384 hours, and cherry pick these charts, taking as gospel that the synoptics will come to pass, especially if there is high pressure plonked over Scandinavia.
But 16 days is an eternity in weather forecasting and what happens on the day is, more often than not, a world away from what was modelled a fortnight before. But it doesn’t stop the blizzard of toys and dummies being thrown out of prams, often by grown men who really should know better that the weather they really want is always 10 days away.
Is this about to change? Probably not but the improved resolution, from 27km to 13km, will massively improve accuracy at short-range.
In the meantime it is perhaps ironic that the final 18z operational run of the GFS 27km resolution model had some of the most mouthwatering solutions for classic cold and snowy winter weather for nearly two years. But, just for a change, the operational is backed up by the ensemble.
Here are most of the 500hPa charts from that last run
This year finished as the second warmest year on record after 2011.
Every month of 2014, apart from August and December, was warmer than average – the means being over 1C warmer every month, bringing the mean temperature to 12.4C, just 0.4C short of the warmest year in 2011 and 1.2C warmer than the 1981-2010 average.
The number of days with thunder was also high. Thunder has been heard in Wanstead on 19 days. In an average year we can expect thunder on only 12 days.
Rainfall is less remarkable although the year has certainly been wetter than average. The total of 746mm puts it in the top 20 per cent of years for rainfall since 1797.
There was occasional respite from the persistent rain
The year began where 2013 left of: wet. Depressions whistling in off the Atlantic brought incessant rain and the wettest January for 130 years. The total, 131mm, which was 2.5 times the average for January, beat the previous record set in 1988 by just 2.8mm. Unlike 1988, January followed a December that was 1.5 times wetter than average – a wet spell that impacted the river Roding where levels ran high.
The most notable day was probably Saturday 25th when what started as a bright, fine day quickly changed around 4pm as a strong squall with heavy rain blew through with associated thunder and lightning and 6C fall in temperature in an hour.
The warm January was followed by an even warmer February with a complete absence of air frost – very unusual for what is commonly the coldest winter month. The conveyor belt of storms off the Atlantic also calmed though not before a storm on the evening of Valentine’s Day saw yet more damage, resulting in two deaths, including a man killed by a wave on a cruise ship in the Channel and a woman killed when a block of falling masonry crushed her car outside Holborn Tube station. The sheer quantity of rain also brought flooding problems around the area. It was also the first winter ever where no snow falling or lying was observed.
The water table appeared to come to the surface on Wanstead Flats in February
The warmest March for 74 years brought lots of gloriously sunny days, a welcome relief from the run of seemingly endless wet months. Just 25.8mm of rain fell over the 31 days – that’s 63 per cent of average. The most notable weather occurred on the 26th when the temperature fell from 10C at 1.30pm to 4C by 3pm. Heavy showers accompanied what was an utterly foul day. The cold pool persisted into the 27th with towering thunder clouds surrounding Wanstead, north, east and south.
The month ended with warm, sunny weather – the southerly flow bringing Saharan dust that deposited on cars.
April continued this year’s theme of being milder than normal; the mean temperature of 12C was 2.2C above average, making it the third warmest April since 1797.
April continued the dry theme of March. Just 19.6mm on rain fell over the 30 days – that’s 46 per cent of average.
The month saw some stunningly sunny days during the second week into the third week, though these were tempered by chilly east to north-easterly winds. The warmest day was the 21st when 21.5C was reached – the first ^70F temperature of the year.
May was also mild though the rain returned with 71mm falling – 139 per cent of average – this hindered sunshine totals to 157 hours, the dullest for 10 years. Most notable was the number of thunderstorms with four incidents of daily thunder.
This screen grab shows the thunderstorm at 4pm on May 24th that saw the temperature fall nearly 6C in a matter of minutes
Though it began unsettled June became warm and dry. Just 15.2mm of rain made it the driest since 2000. The month also brought some spectacular cloudscapes thanks to the high level of thundery activity elsewhere. Though Wanstead did not hear thunder there was plenty of activity close by. It is a typical feature of summer that rainfall can vary a great deal across a small area. The nearest official station to Wanstead, St James’s Park 8.4 miles to our south-west, recorded 33.8mm – more than double what fell here.
June was marked by some spectacular cloudscapes and sunsets. This was the view across Wanstead Flats from Centre Road looking toward Ilford on the 21st
Yet another occasion of impressive cloud formation during June included this example of late evening cirrus. The formation, seen at ground level, seemed similar to a display of the Aurora.
July brought perhaps the most spectacular of our weather. A heatwave brought much thundery activity in what was the 9th warmest July since 1797.
The month was marked with spectacular thunderstorms and torrential downpours, contributing to what was a much wetter than average month – some 73mm fell which is 168% of the monthly average. While on paper the month looks very wet it should be noted that 52% of the July total fell in two episodes: a stalling warm front on the 10th and a cloudburst on 25th. I was away for the thunderstorm though a friend remarked that the roads close to Redbridge Roundabout were like torrents, the rain was so intense for a short period.
The hottest day in July and the year was the 18th with 32.7C recorded. There were 12 occasions where the mercury reached or exceeded 80F.
Perhaps the most impressive thunderstorm was the development of the MCS that moved up from France during the evening of July 18th. There were numerous superb pictures but my favourite is probably this shot taken by Richard Dixon.
This shot was taken by Richard Dixon in Whitstable, Kent. It shows, perfectly, the contrast betweeen the bright orange sunset and the impending doom of the approaching MCS from the continent
What had been a superb summer abruptly ended in August which ended cool, wet and dull. The month, the only one this year that was cooler than average, was characterised by frequent rain and the coldest August night for over 20 years.
More thunderstorms also made it a wetter than average month – some 76mm fell which is 152% of the monthly average and the wettest for 4 years. A couple of nights were notably cool for August: 5C was recorded during the early hours of the 23rd – the coldest August night since 1993.
It was yet another month where rainfall totals could vary greatly in the space of just a few miles. On the 9th a station in Woodford Green recorded 24.4mm, double what fell in Wanstead. The legacy of TS Bertha coincided with the end of our extended hot spell
On 25th a perfect curl could be seen on a depression centred off the west coast of Ireland. The rain associated with this low pressure brought the month’s highest daily rainfall total: 23.4mm (the system bringing 27.5mm) – a thoroughly miserable Bank Holiday Monday where it rained ALL day, from 6am until 9.30pm. It was yet another example of how much even frontal rainfall can vary over a small area with St James Park recording 38.2mm.
Sunset overlooking Wanstead Flats 2nd August
In terms of weather events September was a warm and relatively quiet month save for the two thunderstorms that seemed to mark the Scottish Referendum as the results became apparent in the early hours of Friday 19th. The most notable storm happened around 3pm which brought 24.5mm of rain with a peak rate of 76.5mm/hr at 15.47. The storm ended a run of 16 dry days. Explosive convection brought hail and rain and flooding to Hackney, Hackney Wick and Leytonstone. This storm was the result of a convergence line over London between light southerlies to the south and easterlies to the north – the heavy rain was very localised.
The month was marked with lots of dry, sunny days, the two thunderstorms on the 19th contributing 89 per cent of the rainfall for the month. It was dryer than average – the 44.8mm that fell is 86 per cent of what we would expect in a normal September. Despite this it was only the driest September here since 2011.
Save for the warmest Hallowe’en on record and a notable depression on the 21st October was a relatively quiet month.
The dry and sunny start was replaced with a very unsettled regime at the end of the first week which lasted until the end of the second week – with 39.5mm of rain falling over the 12th and 13th, a notable total for this region. It was wetter than average: 82.4mm represents 123 per cent of what we’d expect to fall in a normal October. The warmest day occurred on the 31st with 21.5C recorded. Many nights were warm with date records matched or broken. Cold nights, relative to the time of year were few.
The final month of autumn was most notable for its rainfall with 19 consecutive days of measurable precipitation and just four completely dry days .
November 22nd by Perch Pond. Drizzle early morning couple with damp air left mist floating above the surface
November was warmer than average; the mean temperature of 8.9C was 0.9C above average, making it the 19th warmest November since 1797: 2.2C warmer than last November, though only the warmest since 2011.
The sunny and warm start on the 1st was quickly replaced with an unsettled, cooler regime week which lasted for nearly three weeks. A brief respite on the 20th was followed by more rain – with 12mm and 15.2mm on the 22nd and 23rd. It was wetter than average: 97.5mm represents 165 per cent of what we’d expect to fall in a normal November.
Despite it being wet it was only the 40th wettest November in the series back to 1797.
The warmest day occurred on the 1st with 17.2C recorded. The first frosts of autumn were recorded. The lowest temperature occurred on 24th when the mercury fell to -1.5C.
Sunshine was average with 60.5 hours recorded – that’s 103 per cent of mean. The sunniest day was on the 4th when 6 hours of sunshine were recorded.
It was the sunniest December on record in the series going back to 1979. Some 11 mornings were completely clear at the 9am observation time
This December was the sunniest on record in my series going back to 1877. Over 90 hours of sunshine were recorded in this area which is 224% of what we can expect to see during an average December.
Mean temperature for the month was average at 5.8C (0.2C above the 30-year average). Rainfall of 39.9mm was 75% of average – the driest since 2010.
The month was 0.7C cooler than last December – with just under half the rain that fell in that wet and stormy month.
December was warmer than average with a mean temperature of 6.5C (0.9C above the 30-year average) – ranking it 33rd in the series since 1881. Rainfall of 81.9mm was 154% of average – ranking it 22nd in the series.
The month was 1C warmer than last December – with 84% of the rain that fell in December 2012.
The first day of December was cloudy, dull and dreary with drizzle in a keen east wind. The following days alternated between rain and sun and some night frost. On the 6th the day started sunny with just a few cirrus clouds – overnight frost persisted all day in garden with a grass min at -2C. The 9th began sunny after a hard frost but then the temperature climbed for 19 hours with cloud building and brief rain at 2am before the cold front passed.
Boxing Day was cloudy and cold before rain, with snow in the north, spread in in the evening. A cold front whistled through about 12.40am on the 27th but not before the warm sector raised the temperature to 8.9C
The wettest day occurred on the 11th. The day started sunny but blustery showers blown in on strong WSW winds coupled together with 6 hours of rain overnight produced 11.5mm.
Things turned much milder in the 3rd week with frequent, chiefly light rain, abundant sunshine and an absence of frost. On the 18th the temperature reached 14C.
Christmas Eve saw the weather begin to cool down again with progressively colder nights. Boxing Day was a cloudy, cold day with rain spreading in during the evening and a notable warm sector raising the temperature to nearly 9C at midnight. The first lowland snow of the winter was reported up north. The month ended with long sunny days and sharp frosts, a couple persisting through the day.
With the 10th anniversary of the Boxing Day Tsunami this year it has often occurred to me whether the British Isles has suffered from a similar catastrophe in centuries gone by.
The ‘Extraordinary Phenomenon’ reported in the Morning Post, Wednesday, June 5, 1811
With such a vast coastline it is certainly possible but written records of any events seem to be scarce. An entry in Luke Howard’s Climate of London, however, suggests that a phenomenon very similar to what happened in Asia in 2004 happened on our shores.
An entry on May 31, 1811, in Howard’s diary describes an “Agitation of the sea at Plymouth” that began at 3am – the sea fell instantly 4ft and immediately rose 8ft. “Universal consternation” pervaded the whole port, vessels in Catwater were thrown about in the greatest confusion with many dragging their anchor; some drifted and several lost their bowsprits and yards.
At 6.45am the sea rose to the height of 11ft and again receded. At 9.30am the tide suddenly stopped and suddenly ebbed 6 inches. At 10.30am it ebbed again in the same manner and then flowed to high water.
At the time it was noted that two gales from the SSW and E preceded this phenomenon but at the time it happened the wind was light from the SSW.
A few days later, on June 8th, the tide was again seen to flow and ebb several feet in as many minutes which continued at intervals over 4 or 5 hours. Immense swells were seen to flow into the harbours of Sutton Pool and Catwater at a rate of 4 knots an hour. During the time of the boar thunder and lightning was “excessive”.
These events coincided with a volcanic eruption near the shore of Ferraria, São Miguel, creating the short-lived Sabrina Island named after the British frigate HMS Sabrina, whose captain, Commander James Tillard, first identified the island and claimed it for the United Kingdom. The eruption caused destruction to many homes. The islet itself disappeared in the following years.
The event isn’t on record as being a tsunami but the symptoms seen in Plymouth all those years ago are similar, albeit on a much smaller scale, to those seen across Asia in 2004.
Could a tsunami affect the UK in the future? The British Geological Survey says not.
Signals for winter have always been well reported by the media. Back in the 1980s weather anoraks across Britain would wait with bated breath to read Bill Foggitt‘s latest prognostications for the coming winter. Though Foggitt had some success his observations, among other weather ‘gurus’, often amounted to weatherlore that has only a slightly greater than evens chance of being right.
One popular myth is that very large blackberries mean a harsh winter. The fact that this has more to do with plentiful rainfall plumping up the fruit at harvest time is ignored.
Colin Finch’s 38F minus rule is altogether different and provides a very good guide to the kind of weather we can expect in January and February. For the rule to work the maximum temperature must be 38F (3.3C) or less for four consecutive days before Christmas Day.
Colin, an amateur meteorologist who passed away in 1991, spent much time researching his rule in the 1970s. He found that most of the coldest winters since the end of the second world war gave a hint of things to come in the weeks leading up to Christmas: the Decembers of 1946, 1955, 1962, 1968, 1969, 1978 were all followed by cold late winters. In 1984 and 1985 the cold spell arrived at Christmas. Other years to loosely follow the rule, 1986, and 1990.
A few weeks ago I was reminded about Colin’s findings and decided to have another look, using daily record data for this area stretching back to 1806.
The results were surprising. If there is a run of cold days (3.3C or less) around mid-month the chance of an average to colder than average January and February is 94% and 74% respectively. The chance of an average to colder than average March is 96%. Also notable is that the chance of a severe spell in January (4C colder than normal) is 30%.
So much for the figures. What are the chances of a run of cold days between now and Christmas Day?
Sunset Southwark Bridge
Up until this week the weather has been fairly quiet with little rain and cold, often frosty nights. But westerlies are now roaring back in from the Atlantic and could be a hint of what is likely to prevail later in the winter. However, the ‘crunch’ time for the 38F minus rule comes soon after the middle of the month. If a spell of Arctic weather develops at that time, even if it lasts only a few days, then the chances of a major cold spell after Christmas are much higher.
As I write this blog the models suggest that a run of cold days may just be possible. It is also notable that the likelihood of a sudden stratospheric warming event, argued by many to be a precursor for conditions that would favour the development of a cold spell, is increasing with a peak set for mid January.
We’ll see but Colin Finch’s findings all those years ago are fascinating and are still relevant today.
* The following obituary appeared in an edition of Weather magazine, a publication of the Royal Meteorological Society, in 1991.
“Colin Finch – The news of the sudden death of Colin Finch on Friday, 23 August 1991 at the tragically early age of 55 will be received with sadness by Members of the society and readers of Weather.
There is no doubt that Colin was one of the most enthusiastic amateur meteorologists that the Society has ever had and, without seeking publicity for himself, he was responsible for making many other amateur enthusiasts aware of the Society and encouraging them to join.
Colin’s interest in the weather began when he was a small boy and received a considerable boost during the snowy and very cold winter of 1946/47 when he was 10 years old. In 1949, at the age of 13, he began to take regular temperature and rainfall readings and gradually added more sophisticated equipment. His record of daily weather data was unbroken until July 1991 when he became too ill to continue.
When he left school in 1953 he joined the Meteorological Office as a Scientific Assistant at Kingsway and was trained under the keen eye of Dick Ogden. Later, after a spell at Heathrow Airport, he left the Office frustrated by his inability to develop a career because he didn’t have sufficiently good educational qualifications. Instead, he turned to a successful business career but his enthusiasm for weather observing and forecasting increased.
Each day he plotted and analysed synoptic charts compiled from short-wave Morse code transmissions which he took down by hand. In the 1960s and 1970s it was quite normal for him to spend Saturdays plotting a chart for the whole of the Northern Hemisphere from Morse broadcasts. Later he had facsimile and satellite-receiving equipment installed at home.
By the late 1960s he was liaising with local authorities and the police in Surrey, warning them of the likelihood of severe weather events. In 1970 he joined the then newly introduced BBC Radio London and every Friday morning he would discuss current weather events and give climatological background data about the week ahead. For these broadcasts he would get up in the early hours to plot a synoptic chart before he went to the studio.
After the broadcasts he would go to the City for a normal day’s work. He kept up this punishing schedule for several years. When the Society introduced the highly successful one-day Saturday discussion meetings in September 1972 Colin was one of the first amateur meteorologists to give a presentation and he was a regular contributor to these occasions. He was an imposing figure, 6ft 4in tall, and was easy to seek out at meetings.”
The final month of autumn was most notable for its rainfall with 19 consecutive days of measurable precipitation and just four completely dry days .
November 22nd by Perch Pond. Drizzle early morning couple with damp air left mist floating above the surface
The month was warmer than average; the mean temperature of 8.9C was 0.9C above average, making it the 19th warmest November since 1797: 2.2C warmer than last November, though only the warmest since 2011.
The sunny and start on the 1st was quickly replaced with an unsettled, cooler regime week which lasted for nearly three weeks. A brief respite on the 20th was followed by more rain – with 12mm and 15.2mm on the 22nd and 23rd. It was wetter than average: 97.5mm represents 165 per cent of what we’d expect to fall in a normal November.
Despite it being wet it was only the 40th wettest November in the series back to 1797.
The warmest day occurred on the 1st with 17.2C recorded. The first frosts of autumn were recorded. The lowest temperature occurred on 24th when the mercury fell to -1.5C.
Sunshine was average with 60.5 hours recorded – that’s 103 per cent of mean. The sunniest day was on the 4th when 6 hours of sunshine were recorded.
Over the next couple of weeks speculation on Christmas Day weather will inevitably build. Will Christmas be white or green?
Shoulder of Mutton pond, Wanstead Park
At this range it is impossible to tell from standard meteorological models though from the 15th, 10 days before the big day and when models can start to be relied upon for at least a general trend, the pieces of the weather jigsaw will start to fall into place.
Latest odds offered by bookies William Hill for a single snowflake at London Heathrow are currently 8-1, slightly longer than I’d expect at this time of year. With high pressure building and a general cooling trend this week I’d expect those odds to start to come down.
In terms of proper snow falling and settling, there has not been a white Christmas in Wanstead for over 30 years. In 2010, we could still see the Christmas card Victorian snow scene in small patches if our gardens, but these were leftovers of a previous dump, so it doesn’t count. Frustratingly, there has been snow on several Boxing Days in Wanstead (1995 and 1996) and in the weeks running up to Christmas, but not on Christmas day itself. The most typical Wanstead Christmas day weather is mild and dry, although it has rained on 12 of the last 33 Christmas days.
The period just before Christmas last year was very stormy
In an earlier blog I had a look at what the last 170 or so Christmas Days in London were like weatherwise and found that snow actually falling on the day is extremely rare. Since 1840 there have been just 19 occasions of snow or sleet falling on the capital on Christmas Day which equates to a probability of just under 11%. If you consider that the last ‘white Christmas’ (see note) was in 1996, then we are well overdue one.
But the weather doesn’t adhere to human created calendars and behave like it should on any given day. But patterns in any given year can sometimes repeat though correctly predicting they will happen is more down to luck. Nevertheless I’ve had another look at my calculations for this winter and see if there is any way I can make a prediction for Christmas Day.
I firstly had a look at Christmas Day stats overall since 1840. The most common group of maxima in the series is 8.1C and above. This occurred 69 times or 40%. I then had a look at the years that most closely follow this October and November. None of the years saw a white Christmas, however it is interesting to note that five out of the six years saw some snow during the month. Snow often falls before and after Christmas. Why that is no-one knows.
So my guess for the weather on Christmas Day this year is for a maximum temperature of 6C after an overnight low of around 0C. With a little rain likely I suppose there is a chance of at least something sleety falling though I’d be surprised if, on Christmas Day morning, we pull back the curtains on a wintry Dickensian scene.
* The definition of a white Christmas used most widely – notably by the bookies – is for a single snowflake, even if it lands in the midst of heavy rain, to be observed falling in the 24 hours of 25 December at a specified location recognised by the Met Office.
** On average, snow or sleet falls in the UK 5 days in December, compared with 7.6 days in January, 6.8 days in February and 6 days in March. White Christmases were more frequent in the 18th and 19th centuries, even more so before the change of calendar in 1752, which effectively brought Christmas back by 12 days. Climate change has also brought higher average temperatures over land and sea and this generally reduces the chances of a white Christmas.
There is a higher chance of snow this year. The average for lying snow in Wanstead at 9am in winter is 6 days
Probabilities for winter for the London area would be a more apt title for this post but that’s not very exciting compared with the hyperbole published almost daily by the likes of the Daily Express.
Much has been written about the sources of their forecasts over the past couple of years. Splash headlines that promise Armageddon Arctic conditions or Biblical blizzards never seem to materialise. So without boring you further I’ll move on to my own views on how I think the next 90-odd days will unfold.
Taking into account more sophisticated methods than my own there seems to be a signal for something colder than last year – though that’s not saying much given that 2013/14 was the 11th warmest winter on record with NO snow falling observed in this area.
Jack Frost could also be around more this winter than last
Though it was abandoned by the Met Office years ago I have decided to base my predictions more on analogues this year. I have a lot more data at my disposal – the series I use now extends past 1881 back to 1797.
The figure I arrived at, taken as an average of the closest matching autumn periods, is a mean temperature of 4.2C with rainfall totalling 156mm over the months of December, January and February – that’s about a degree colder than average and about average rainfall – though I think it could be less given that December is looking relatively dry on the current model output.
The probability of a winter with a mean temperature of between 3C and 4C is 33% – the most likely outcome – though this low figure emphasizes the mixed signals this autumn. With this in mind a winter similar to 1984/85 is possible which saw a brief cold snap at the end of December together with a two-week cold spell that began during the first week of January. There was also a 10-day cold spell during February of that winter.
To try to add value to the above outcome I also had a look at the likelihood of this winter being as mild as last winter.
It has been noted in the past that mild winters often come in twos. I had a look back through the series to see if this was true.
The occurrence of two very mild winters in succession is 27/217 (12.4%). The occurrence of a very mild winter being followed by a very cold or severe winter is 16/217 (7.4%). So while, from these simple stats, another mild winter is more likely, it is not really high enough to consider over the average I found in the first calculation made from straight autumn statistics.
A final fact to consider is just how mild and wet this year has been. Every month this year, apart from August, has been warmer than average by an average factor of 1.2. If December continues warm this year could possibly end as the warmest on record. However, it is also possible that nature is about to redress the balance.
* Forecasting models use probability on any given outcome. Millions of observations are fed into the Met Office database (and other countries’ weather agencies) every day. Supercomputers then crunch through this data to give probable outcomes. With the volatility of the atmosphere it is not surprising that certainty of any outcome often falls away rapidly. Forecasting has improved greatly in the last 20 years – though anything the models churn out beyond three to five days should be handled with caution. Long range models can give *some* idea of general trends for the months ahead – but changing just one variable can vastly alter an outcome at the end of the run.
* *Over the past few months I have been collating data for the area around Wanstead. This data is freely available from the excellent Met Office library and is emailed via Excel spreadsheet. Rainfall stats include a near-complete daily archive, stretching from 1961 to 2003, from City of London Cemetery . Sadly the rainfall station, along with many others, ceased to supply the Met Office after cuts were made shortly after the turn of century. Prior to 1961 I have used monthly figures taken at the Greenwich Royal Observatory stretching back to 1881. Though this is 6 miles away the difference in temperature between the two areas would be miniscule compared with rainfall data and so can be used. I use my own stats for the period after 2003.
Christmas in Victorian London is often portrayed as very cold and snowy – picture perfect images of Yuletides past always scream out at us every year we open a box of Christmas cards.
The Temple, Wanstead Park, always looks that much more stunning with a covering of snow
But a look back through the meteorological records of the Royal Observatory at Greenwich reveals a very different reality.
The 1840s and 1850s, decades where most Christmas traditions marked today began, were often very mild, wet and windy – indeed before 2015 the warmest Christmas Day maximum temperature at Greenwich occurred in 1852 when the mercury reached 13.3C.
Like modern times, however, there were exceptions and 1840 was very cold – the record for Christmas Day mentions “trees coated with rime (ice) 3/8 inch thick”!
The following 20 years saw Christmas morning much milder – well over half had maxima of 6C or higher. In 1843, the year Charles Dickens first published A Christmas Carol and the public sent their first Christmas cards, the temperature reached a balmy 10.1C – though dense fog probably made it feel at least a bit more seasonal.
Frost is a common feature of Christmas Day
Four years later in 1847, the year the capital’s Tom Smith invented the Christmas cracker, things were a bit colder – a high of 4.2C and overcast with rain late evening. The following year an image of Victoria and Albert celebrating with their family around a Christmas tree appeared in the Illustrated London News. Like many things Royal down the years it really captured the public’s imagination of taking a spruce or similar evergreen into their living rooms and decorating it every Yuletide.
Christmas two years later, in 1849, was at least cold enough for something wintry to fall. London, however, was still coming to terms with its worst-ever cholera outbreak. With around 14,000 deaths from the disease Christmas was probably not a high priority that winter.
When Good King Wenceslas was first included in Carols for Christmas-Tide in 1853 the day was cold but there was still no “deep, crisp and even” snow or “rude wind’s wild lament”. The day stayed calm and clear.
Though the period either side of December 25th began to be marked with cold, snowy spells it would be another 11 years before London experienced its first official white Christmas in 1864. Sleet, which fell at the end of a 4-day cold spell, probably added to the drama of swimmers taking part in the first Christmas Day swim in the Serpentine, Hyde Park. With a high temperature of just 1.4C it’s quite feasible the few who braved it probably had to break the ice before they took the plunge.
Five years later London experienced another white Christmas with snow falling in a north-easterly breeze – the start of a four-day cold spell.
The joint-coldest Christmas Day on record followed in 1870 with a mean temperature of -7.2C. The building of the Royal Albert Hall was scheduled to be completed by December 25th but it was not until March 29th 1871 that it was officially opened by Queen Victoria.
The remainder of Victoria’s reign was marked with far more white Christmases, a period where nearly two-thirds of Decembers were marked with extended cold, snowy spells. Fog and frost were also frequent.
With a new century and new monarch Christmas-time turned milder and London would have to wait until close to the end of Edward VII’s reign in 1909 to see a ‘white Christmas’ – a poor affair with just a bit a sleet mixed in with the rain late morning. Many probably failed to notice it but it still counts as a white Christmas according to modern bookie’s standards.
Christmas Day can also be stormy
Four of the 26 Christmas Days of George V’s reign were white but the mean temperatures suggest they were all marginal affairs – the core cold weather happening either before or after the 25th. Of note also is the dominance of south-westerlies that brought mild and wet weather – nine out of ten Christmas Days in the 1920s saw rain falling – far in excess of the average for rain on Christmas Day which is 47 per cent.
Just one Christmas was white during George VI’s reign, a ‘good covering of snow’ was recorded by observers at Greenwich in 1938 – the snow falling at the end of a 7-day cold spell.
Sunshine was not a dominant feature of Christmas Day prior to Queen Elizabeth II coming to the throne – the average total in Greenwich from 1877 to 1951 was just under 0.8hrs. Yet the average sunshine total for Christmas Day for the first four years of Elizabeth’s reign jumped to 5.2 hours. The 6.5 hours on Christmas Day 1952 is a record that still stands today! It is remarkable that this record was set just over a fortnight after the Great Smog contributed to the deaths of 4,000 people though other studies put the figure at 12,000 people.
The Clean Air Act 1956 ironically saw the return of dull Christmas Days – though 1956 was a white Christmas with a light covering of snow and a maximum of zero Celsius.
White Christmas Days that followed included 1957 (showery sleet), 1964, 1968 (sleet), and 1970.
Christmas Day 1976 was the last time snow actually fell on Christmas Day in this area though, officially, the last white Christmas was 1996 when a few sleety flakes fell in the early morning.
Christmas Days since then have been mostly mild affairs in London. Of course we had a taste of what a Dickensian Christmas Day was like four years ago when the mean temperature for the day was -1.9C. There were still small patches of snow in our gardens but these were leftovers from a previous dump, so it doesn’t count as a white Christmas. Frustratingly, there has been snow on several Boxing Days in Wanstead (1995 and 1996) and in the weeks running up to Christmas, but not on Christmas day itself.
The warmest Christmas Day in this area occurred in 2015 when a maximum of 15.2C was recorded. Warm air sourced from off the west coast of Africa sent dew points soaring, the minimum on Christmas Day night into Boxing Day did not fall below 13.5C, another record.
The synoptic chart for 0000z Christmas Day 2015 shows ever-warmer air being pumped northwards over the British Isles.
It is surprising how varied the weather can be on Christmas Day – we always think that Yuletide in the ‘Olden Days’ was a cold affair but a look back to 1840 reveals there were times when it was just as mild as it has been in recent years.
Christmas Day morning 1927: the wettest with some 24.9mm recorded
* Statistics for every Christmas Day since 1840 can be found here.
** The definition of a white Christmas used most widely – notably by the bookies – is for a single snowflake, even if it lands in the midst of heavy rain, to be observed falling in the 24 hours of 25 December at a specified location recognised by the Met Office.
*** In the past 170-odd years there has only been 19 white Christmases: in 1864 (sleet), 1869, 1876, 1878, 1884, 1895, 1909 (sleet), 1916, 1919, 1925, 1927, 1938, 1956, 1957 (sleet), 1964, 1968 (sleet), 1970, 1976, 1996 (sleet)
Save for the warmest Hallowe’en on record and a notable depression on the 21st October was a relatively quiet month.
The month was warmer than average; the mean temperature of 13.7C was 1.9C above average, making it the 5th warmest October since 1797: 0.7C warmer than last October, though only the warmest since 2011.
The dry and sunny start was replaced with a very unsettled regime at the end of the first week which lasted until the end of the second week – with 39.5mm of rain falling over the 12th and 13th, a notable total for this region. It was wetter than average: 82.4mm represents 123 per cent of what we’d expect to fall in a normal October.
Despite it being wet it was only the 74th wettest October in the series back to 1797.
The warmest day occurred on the 31st with 21.5C recorded. Many nights were warm with date records matched or broken. Cold nights, relative to the time of year were few. The lowest temperature occurred on 4th when the mercury fell to 2C – a ground frost was narrowly avoided with the grass minimum thermometer falling to 0.2C.
Sunshine was slightly below average with 103.6 hours recorded – that’s 97 per cent of mean. The sunniest day was on the 5th when 9 hours of sunshine were recorded.
Luke Howard‘s The Climate of London describes a similar such event that took place on September 7th, 1820. Howard describes how the thermometer fell from 68.5°F to 62.5°F. After making observations at his home in Tottenham at 10.30am Howard made his way to Stoke Newington to visit fellow scientist and Quaker, William Allen, to observe and record the eclipse.
Howard noted that the lowest temperature was observed about seven minutes after the greatest obscuration. He also mentions that his son noticed that spots of light falling through the shade of trees were in the shape of crescents, mirroring the lunar disc across the sun, rather than globular. He also states that Venus was very easily visible during the eclipse.
Wanstead Meteo 
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