Tag Archives: East London weather statistics

London’s February extremes since 1959

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of February.

Probably most notable is the cold February of 1991 which saw the deepest snowfall I can remember – days of snow saw the level depth past my knee in suburban London. February 1986 was also very cold but also very dry with little snow.

Februaries in the 1990s were also often warm with 19.7C being reached in Wanstead on 13th in 1998. I wonder when we will see the first >20C recorded?

It is a shame that the Met Office only publishes easy to access daily data in Excel format back to 1959 as this obviously omits the classic snowy February of 1947 which is worth a blog on its own.

My winter forecast for the London area can be found here.

Some national UK February values according to TORRO

Hottest: 19.7C Greenwich – 13th 1998
Coldest: -27.2C Braemar – 11th 1895
Wettest: 196.6mm Ben Nevis, Highland – 6th 1894

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Wanstead Weather: 2017 review

This year finished as the 10th warmest on record – some 0.7C warmer than the 1981-2010 average. Screen Shot 2018-01-05 at 12.54.53

Only three months of 2017 were roughly average – the means being within +/-0.7 every month, bringing the mean temperature to 11.9C.

Rainfall was less remarkable with the year finishing roughly average. The total of 607mm (101% of 1981-2010 average) puts it as the 119th wettest since 1797, just over 40mm wetter than 2016.

It was also a slightly duller than average year with 1,391.2 hours of sunshine recorded. That’s 94 per cent of average, the 91st sunniest since 1881.

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For a review of each month, click January, FebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovember, December

To view full stats follow this link:http://1drv.ms/1kiTuzv

You can read the national review of weather events at the Met Office blog here.

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London’s January extremes since 1959

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of January.

Probably most notable is just how impressive the depth of cold was during the cold spell of 1987. When considering St James’s Park the temperature on the 12th never rose above -6C: nearly 4C colder than any January day in 1963, the coldest winter in modern times.

My winter forecast for the London area can be found here.

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Some national UK January values according to TORRO

Hottest: 18.3C Aber, Gwynedd – 27th 1958
Coldest: -27.2C Braemar, Grampian – 10th 1982
Wettest: 238.4mm Loch Sloy main adit Strathclyde – 17th 1974

Climatology

Here’s a couple of graphs showing the maxima, minima and rainfall. Notice the spike  which reflects the singularity which has an 84 per cent probability.

jan av tmax

jan av min

jan av rain

 

Summer 2017 review

Summer 2017 was a season of two halves, the mean temperature of 18.5C (1.3C above average) made it the tenth warmest summer since 1797.

Though it was warm overall it was also wet. Nearly 234mm of rain were collected, 159 per cent of average, making it the wettest summer since 1987.

Just under 535 hours of sun were recorded, 94 per cent of average and the sunniest summer for three years.

summer 2017 mean
The graph of the mean temperature for the 3 months shows a marked decline from the second week of July
summer 2017 rain
There were at least 3 falls of rain greater than 30mm over 24 hours though classic thunderstorms of recent years were notably lacking
summer 2017 sun
Sunshine was broadly average

 

 

 

 

 

Phew! What a scorcher…

I’ve seen this phrase uttered more than once over the past couple of days thanks to high temperatures and humidity. But ask anyone to define a hot day and you’ll get a different answer every time.

Growing up in the 1970s / 80s redtop newspapers would use the phrase once the mercury was nudging 80F (26.7C). But to ‘scorch’ you need sunshine, preferably at least 10 hours of it. Considering statistics from the Heathrow airport climate station in west London there have been 463 scorchers since 1959, the most recent happening on July 5th with 29.5C recorded and 13.9 hours of sunshine. There have now been 9 scorchers this year, already matching the number that were recorded in 2014 and only 3 short of last year.

But even with last month’s heatwave this year has some way to go, however, to match the amount measured in 1976 and 1995: 31 days!

scorchers

 

May 2017: rather warm, average rain

The mean temperature for May 2017 of 14.7C was 1.6C above average; the warmest for six years and the 11th warmest in a local series going back to 1797.

sunset
Sunset on May 1st 2017

Despite the first ten days of the month continuing the dry spell that has plagued London for months the total recorded finished above average: 62.5mm rainfall (122% of the 1981-2010), the wettest May for three years.

Though the month finished warm with some cracking sunny days the first two-thirds of the month were relatively dull: 157.1hrs of sunshine were recorded which is 86% of average, the dullest for 13 years.

I published my summer forecast on June 1st. It’s looking average.

Here follows the full weather diary for May. To view full stats follow this link:http://1drv.ms/1kiTuzv

1st: Cloudy all day with just a few bright intervals.
2nd: Sunny and clear morning, cloud bubbled up at noon. Cloud thickened with very light drizzle at 8pm.
3rd: Cloudy, dull with occasional very light drizzle.
4th: Cloudy and feeling chilly all day. Odd drizzle.
5th: Sunny start though cloud thickened quickly to leave an overcast though bright, breezy afternoon.
6th: Cloudy all day with a couple of bright spells.
7th: Cloudy and cool start, cloud decreasing after noon, eventually clearing to leave long sunny spells at 5pm.
8th: Cloudy and cool start – the cloud sticking all day and felt chilly.
9th: Cloudy and cool start, cloud decreased late afternoon but did not completely clear until 5am, saving area from frost. -2.8C in Benson!
10th: Sunny and mostly clear into the afternoon with patchy cirrus.
11th: Sunny and humid to start with much high-level cirrus. Breezy too. Showers overnight.
12th: Cloudy start, one or two light showers before a brief heavy one at 2pm. Sunny spells developed late afternoon.
13th: Cloudy start before cloud decreased to long sunny spells in afternoon. Cloudier overnight with showers between 7am and 8am.
14th: Sunny spells and breezy. Cloudier overnight with shower at 7am.
15th: Light rain and showers through the morning, clearing in the afternoon to sunny intervals.
16th: Bright start with cloud decreasing. Some very warm sunny spells – felt like summer for first time. Light rain in the evening though it didn’t start falling consistently until 2am with heaviest fall arriving at 4am.
17th: Bright start with plenty of sunny spells. Showery rain arrived at noon, turning more persistent at 4pm, clearing around 10pm.
18th: Bright start with lots of sunshine. Cloud began thickening at 1pm with bursts of light rain. Persistent rain arrived at 3.30pm and was still moderate to heavy at 10pm. Started petering out at midnight but then two further showers at 3am and 5am.
19th: Showery with longer spells of rain. This tended to clear to sunny spells. Thunder in the evening with a brief heavy shower at 6.23pm.
20th: Sunny, warm and breezy morning to 1pm.
21st: Sunny start with cumulus bubbling up. Sunny spells thereafter, growing longer as day wore on. Still 20C at 6pm during first Music in Wanstead Park. Overcast early but cloud started to break around 8am.
22nd: Sunny with decreasing cloud, clear by 1pm with just patchy cirrus.
23rd: Cloudy start with sunny spells mid morning, turning mostly cloudy again though.
24th: Bright start with variable cloud and sunny spells.
25th: Sunny with variable cloud at obs time, the cloud quickly clearing though a convection line could be seen in the west from Essex.
26th: Sunny and clear though breezy. Long sunny spells through the day. Feeling hot. Thunder and brief downpour between 8.30am and 9am.
27th: Sunny though only after front had cleared. Then alternating cloudy to sunny. More cloud late afternoon and not feeling as nice as forecast.
28th: Sunny start with variable cloud though the day. Rain in the evening before storm arrived at 1am, the rain turning heavier at 1.45am and lasting till just gone 3am.
29th: Cloudy start though soon turning brighter. Feeling humid with occasional very light rain.
30th: Cloudy but bright with the odd break. Feeling fresher
31st: Bright start with plenty of holes in the alto cumulus. Cloudier in the afternoon

April 2017: seventh driest since 1797

The driest April since 2011 was also the seventh driest in a local record going back to 1797. Just 4.3mm fell, nearly half of which was recorded on the final day.

An ‘absolute drought’ that began in March coincided with the month; a run of 26 days with a daily total of <0.2mm! Dry early springs seem to be becoming a pattern in this area with eight of the last 11 Aprils being notably dry.Screen Shot 2017-05-02 at 21.14.02

Though the mean temperature for April finished a fraction above average – 10.6C is 0.8C above average – it was a month of two halves. The month started warm with the temperature peaking at 25.4C on the 9th – Sunday of what was a warm weekend in London.

A polar low on 24th brought an unseasonably cold end to the month with cold days and night frost. Thunder was recorded on 26th and was accompanied by <5mm hail.

The total sunshine hours were just above average: 178.4 hours is 111% of the 1981-2010 average

The wettest day occurred on the 30th with 2mm.

Air frosts: 1, Ground frosts: 7Screen Shot 2017-05-02 at 21.34.19

Looking ahead, I think May will be another slightly milder than avrage month and continuing much drier than average.

Here follows the full weather diary for April. To view full stats follow this link:http://1drv.ms/1kiTuzv

1st: Cloudy into the late morning before some cloud breaks appeared. Brief shower and some warm sunshine but cooler than lately. Cold in early evening and cloud breaks overnight.
2nd: Sunny with variable cumulus. Variable cloud through the day and chilly overnight
Sunny with bubbly cumulus.
Screen Shot 2017-05-02 at 21.35.103rd: Cloudy but with bright breaks and blue sky in distance.
4th: Sunny and pleasant early with bubbly cumulus – this lasted all day.
5th: Sunny with just a few cumulus.
6th: Sunny with just a few wispy cumulus floating around, slight haze.
7th: Sunny and gin clear.
8th: Sunny spells with a few cumulus. Much cooler.
9th: Sunny with some cirrus and cumulus.
10th: Sunny though with lots of cloud at times.
11th: Sunny start then clouded over then sunnier again with cloudier periods.
12th: Early sunny spells, the cloud thickening by 11.30pm to leave a mostly cloudy afternoon.
Screen Shot 2017-05-02 at 21.33.4513th: Cloudy though high base made it seem bright. Feeling chilly. A shower overnight.
14th: Bright start though with plenty of cloud around. Clear spells overnight.
15th: Sunny early though cloud increasing – a very light shower at 2.15pm.
16th: Cloudy, dull and cool. Some brightness at 2pm but then cloud thickened and breeze freshened to leave a cold afternoon.
17th: Sunny with variable cloud – clear overnight with ground frost.
18th: Sunny with broken cloud to start.
19th: Sunny start but clouded over, then sunny intervals.
20th: Cloud and mild all day.
21st: Very light drizzle to start then heavy cloud. Drizzle turned to light rain in Beckton but dry in Aldersbrook.
22nd: Bright start with broken cloud.
23rd: Bright early with patchy cirrus and altocumulus then completely cloudy and chilly. 24th: Some spots of rain around before moderate shower arrived at 5pm with 0.54mm falling.
25th: Sunny, clear start in polar air before cloud bubbled up around 10.30am. Then sunny spells – dew point stayed around or below freezing all day.
26th: Overcast and chilly with a cold breeze.
27th: Sunny, frosty start but cloud quickly bubbling up. Felt chilly.
28th: Mostly cloudy with the odd sunny spell
29th: Bright start but quickly turning cloudy
30th: Sunny early but gradually clouded over with rain at 1am. This stopped around 2am with small fall before 9am.

October 2016: average temps, dry

October 2016 was yet another dry month, a pattern that has emerged since the middle of June. Just 52 per cent of the October average was recorded.

sunny
October saw many pleasantly sunny days

The monthly mean finished 11.5C, 0.3C above average and ending a three-month run of warm temperatures.

Some 105 hours of sunshine were recorded, 98 per cent of average

Air frosts: 0, Ground frosts: 0

So what has November got in store weatherwise? The models on the 1st suggest an anticyclone anchored to our west over the Atlantic will bring a regime of, at times, chilly northerly winds and the potential for rainfall, much probably in the form of showers, driven by low pressure in the North Sea. Where skies clear at night there will be potential for the first air frosts of the autumn.

Beyond the grasp of the models my long range outlook method suggests an average or cold month is most likely: average and cold are both 30 per cent probability. Rather cold and severe are both 20%! There appears no chance of anything mild.

Rainfall appears that it will be skewed toward something above average at 40 per cent, though average and below average are both 30 per cent.

Sunshine looks average at 57 per cent probability.

So, to sum up, we’re looking at a mean of 6.8C, rainfall: 55mm, sunshine: 41hrs.

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Numerous holes dug by squirrels appeared in October. The squirrels have no more an idea than we do whether winter will be cold

Here follows the full weather diary for October…Full stats for the month here:http://1drv.ms/1rSfT7Y

1st: Rainy start with showery bursts to 11.25am then through afternoon mostly cloudy.
2nd: Sunny but chilly, feeling very autumnal. Clearing into the evening with a cold night to follow.
3rd: Sunny, gin clear all day until 2.08pm.
4th: Another sunny albeit slightly hazy start then patchy cumulus. Warm in the sunshine even with a easterly breeze.
5th: Sunny start though breezy and with quite a few cumulus around. Cloud streets observed at 10.30am, the cloud tending to decrease and completely melt away by 4pm.
6th: Sunny start but with much cloudier spells at times. Warm in the shelter.
7th: Cloudy all day, the cloud thick enough at lunch time for drizzle that damped the ground.
8th: Cloudy with bursts of light drizzle in the morning, some brightness. A heavy shower at 2pm was brief then cloudy. Clear and cold overnight.
9th: Sunny until 2pm with patchy cumulus – a really glorious morning. Sunny spells in afternoon with cold night to follow.
10th: Sunny with just patchy cirrus first thing. Thick patches of alto-cumulus drifted across from time to time. Cold overnight.
11th: Sunny with patchy cumulus which melted away through the day. Showers after dark, one at 2330z.
12th: Cloudy and damp start. Short, sharp shower at noon then mostly cloudy.
13th: Rainy , wet start thanks to a streamer of moderate to heavy showers.
14th: Cloudy am but with lots of sunshine mid-morning before clouding over again though staying bright.
15th: Bright start but with lots of cloud pushing in and light burst of drizzle at noon. Cloud thickened before rain moved in after 5pm and fell intermittently through the night.
16th: Damp start as the remnants of the overnight rain cleared away, then becoming brighter at 11.15am. Sunny spells for a time before turning cloudier with some very sharp showers on yet another convergence line.
17th: Cloudy start but soon brightening up with some pleasant sunny spells. Heavy burst of rainfall at 5.30pm with more showers at midnight and early hours.
18th: Cloudy though quickly turning bright and breezy with long sunny spells after clearance of the cold front.
19th: Bright start though more cloud around than sun all day. Feeling colder than of late.
20th: Bright and breezy with variable cloud and sunny spells. A short shower at 2pm damped the ground. Clear spells overnight made it chilly. A shower at 9.30am.
21st: Cloudy and chily start.
22nd: Cloudy and cold start, brief clearance at 11am then sunny spells.
23rd: Sunny and clear to start though cold. Sunny spells into the afternoon. Cloudy overnight.
24th: Cloudy and cool during the day and overnight.
25th: Dull and cloudy with only limited brightness. Clear early evening with temp falling before it turned misty. Cloud pushed in raising the temperature.
26th: Cloudy start and turning very dull before bright spells spread in at noon.
27th: Cloudy though getting brighter through the morning with a brief clearance at noon, then bright and sunny intervals.
28th: Sunny and very mild to start. Sunny spells through the day.
29th: Cloudy start with bright intervals after midday. Clear spells after dark with fog forming after 11pm which gave a foggy start.
30th: Foggy start then cloudy and miserable.
31st: Fog to start then clearing at 11am. Gorgeous sunny day thereafter.

September 2016: very warm, very dry

Last month was the second warmest September in a local record going back to 1797! The monthly mean finished 17.8C, 2.4C above average. Despite being an ‘autumn’ month September was actually a full degree warmer than June!

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September 2016 was the second warmest in a local record back to 1797, though we’re talking by fewer than tenths of a degree.

The hottest September day since 1959 was recorded on the 13th when 33.1C was reached, the sixth equal hottest in the local daily record back to 1848.

The month also saw the warmest minimum recorded since 1959 when the mercury failed to fall below 18.7C on the 6th.

It was another very dry month, the third much drier than average month in a row: just 27.7mm fell, 24 per cent of average, making it the driest September since since 2007 and the 12th driest in the local record.

Like August, the month only falls down in terms of impressiveness when sunshine hours are considered. Some 119 hours were recorded, that’s 85 per cent of average, making it the dullest September for 15 years.

Air frosts: 0, Ground frosts: 0

So what has September got in store weatherwise? The models on the 1st suggest that a large Scandinavian high will become established to our NE bringing lots of settled weather and showers on coasts. There’s obviously the chance of trough disruption as the month progresses if the anticyclone’s influence declines.

Beyond the grasp of the models my usual long range outlook method falls down this month due to September’s warmth and dryness – there is nothing within  +/- 10% of September’s statistics. I would guess, however, that we are looking at another drier than average month with frost becoming a risk as the month progresses where skies clear. There is also the chance of more pleasant autumn days where skies are clear during the day.

My September outlook for temperature was poor. I predicted a mean of 15.3C (outcome: 17.8C). It was much, much drier than I thought: 300mm (outcome: 27.7mm). Sunshine was poor: 140 hours (outcome: 119 hours).

Here follows the full weather diary for September…Full stats for the month here:http://1drv.ms/1rSfT7Y

1st: Sunny start but cloud gradually increased until it was overcast by 6pm. Clear spells overnight but warmer than previous nights.
2nd: Cloudy though some brighter intervals.
3rd: Sunny start, cloud began to pile in at 12.30pm with rain arriving at 5.30pm, this fell through the evening with some showers in the early hours.
4th: Bright, breezy start but rapidly turning cloudy and dull. Some rain overnight.
5th: Light rain and dull to start – this quickly clearing to cloud by 3pm. Things remained cloudy with a muggy night.
6th: Cloudy, dull and muggy start after warmest September night on record. Another warm night though muggy.screen-shot-2016-10-01-at-12-22-03
7th: Cloudy to 11am though sun breaking through as drier air arrived. Feeling humid.
8th: Sunny start but with plenty of cumulus, this quickly decreasing to leave clear sky.
9th: Cloudy morning though sky seemed to periodically clear of low cumulus before becoming overcast and very breezy in the afternoon. Some rain overnight and just before obs time.
10th: Cloudy start with patchy light rain, this briefly turning  heavy at 1pm  before turning occasionally moderate. Dreadful afternoon after recently. Clearing overnight to leave a sunny start.
11th: A glorious sunny day with only the odd patch of cirrus.
12th: Bright start with some sunshine, clouding over with a few splodges of rain with warm front. Then sunny and very warm.
13th: Sunny start with a few cirrus and castalanus around. Breezy at times with the thermals. The warmest September day since 1959 and 6th equal warmest since 1848.screen-shot-2016-10-01-at-12-13-54
14th: Sunny start with a few cirrus. A few patches of alto-cumulus later. Very warm but not as hot as yesterday. Warm, pleasant evening.
15th: Sunny with a few wispy cumulus, clearing to hot sunshine. Some alto-cumulus developed at 2pm and towering cumulus could be seen in distance. Thunderstorms reporting to NW of London. Cloudy and warm overnight with eight peals of thunder in the early hours and heavy rain.
16th: Light to moderate rain through the morning, petering out at 1.30pm.
17th: Cloudy, cool and breezy all day, at times dull.
18th: Cloudy all day, a bit warmer than the previous two days.
19th: Cloudy start though with sun breaking through briefly at 11am until 1pm then cloudy again. Rain at 1am that didn’t last long enough to register.
20th: Cloudy and fairly calm – a nothing day with odd very light drizzle.
21st: Bright start with cloud breaking to long spells of sunshine before more cloud moved in. Warmer than of late.
22nd: Cloudy but  sun broke through giving pleasant afternoon and cool overnight.
23rd: Sunny, gin clear and cold start. Just a few fair weather cumulus through the day.
24th: Sunny start with cloud decreasing. Very warm in sun but cloud and breeze built through the day. Overnight light rain between 6am and 9am.
25th: Bright start after overnight light rain.
26th: Bright start with a few cloud breaks here and there. Heavy shower at 12.15pm with further threat of rain but stayed dry.
27th: Bright start with signs of a cold front moving in from south then cloudy.
28th: Sunny start with patchy cirrus, this tending to thicken at lunchtime to turn mostly overcast with humidity increasing. Breeze also picked up with reappearance of sun mid afternoon. Cloudy, very mild and breezy rest of the day.
29th: Cold front and brief heavy rain swept in at 10.03am. Then intermittent falls until 11.23am.
30th: Sunny, gin-clear start, patchy cumulus bubbling up at 10.30am. Cloud grew thicker around 12 noon with brief shower at 1pm. Then sunny spells and cloudier periods. Another shower just after nightfall then clear. Cloud moved in after 2am with another shower. Early sunshine  gave way to moderate showers around 9.45am.

August 2014 – cool, wet and dull

Anyone hoping for a continuation of June and July’s hot weather would have been left sorely disappointed by last month which was characterised by frequent rain and the coldest August night for over 20 years.

A stunning example of sunlight illuminating the underside of cloud at sunset was seen mid-month
A stunning example of sunlight illuminating the underside of cloud at sunset was seen mid-month

August 2014 was the first month this year to be cooler than average; the mean temperature of 17.2C was 1C below average, making it the 89th warmest August since 1797: 1.6C cooler than last August, the coolest for 7 years.

The month was marked with thunderstorms and heavy downpours, contributing to what was a much wetter than average month – some 76mm fell which is 152% of the monthly average and the wettest for 4 years.

The hottest day occurred on the 7th with 27.3C recorded – nothing special for August and a date that heralded the end of the hot spell during June and July.

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.

Sunshine was below average with 161 hours recorded – that’s 83 per cent of mean. The sunniest day was on the 3rd when 12 hours of sunshine were recorded. Throughout the month there were just 2 days with 10 hours or more of sunshine. There were 4 days with thunder recorded – the average for August is 3.

To view full stats follow this link:http://1drv.ms/1kiTuzv

Looking further afield there were many thunderstorms around the UK though many places missed out on the big downpours. 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 – an excellent analysis of this storm can be found here.

There were some spectacular cloud formations not far from here. A particularly good one was seen in Witham. 

Squally storm line approaching Witham, panoramic shot!

Prolonged heavy rain on the 11th caused extensive flooding in Scotland.

On the 14th ‘Biblical’ flooding affected Lewisham in south east London.

On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. 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.
On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. 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.

On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. 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. The top 30 totals for that day can be seen here.

sunset overlooking Wanstead Flats 2nd August
sunset overlooking Wanstead Flats 2nd August

Looking even further afield four people were killed in a flash flood at an Italian festival early on in the month.