Sunshine of late seems to have been endless with the past 10 days being virtually cloudless from dawn to dusk.
After a very sunny March which saw over 170% of average sunshine recorded at Heathrow April has already seen over 56% of average sun hours in the first eight days.
In terms of the total percentage possible of sun hours the past 11 days are second only to a period in 1990 that stretched from April 27th until May 7th.
The coming winter is likely to be mild and wet overall thanks to a predominant south-westerly Atlantic regime.
While that may sound grim for any snow and cold lovers reading this I would suggest that the possibility of brief cold snaps this season are higher than they have been during the last few winters.
This year I have tried to improve my statistical method by adding warming on to previous years to, hopefully, give better results.
In terms of rainfall and mean temperature a total of eleven years were similar to this October and November, spanning 1826 to 2021.
The probabilities for the following DJF winter were thus.
| Mean temperature | Probability | Rainfall | Probability |
| Very mild | 46% | Wet | 33% |
| Average to mild | 33% | Average | 37% |
| Below average | 21% | Dry | 30% |
London winter forecast 2024/25
Looking deeper into the stats I had a look at the Oceanic Niño Index; no years were similar to this one though the index only goes as far back as 1950 – so no real help.
The prognosis for snow at this point seems bleak – though chances may be heightened should we experience a stratospheric sudden warming in December / January. Though, as seen in 1987 where a vortex ‘split’ was recorded, this would still not guarantee wintry weather.
Looking at the data month to month would suggest the best chance of a cold snap around December 22nd through Christmas before warming up in the New Year. Beyond that I would suggest that the chances of another cold snap in January are higher than they have been for the last few winters. February, however, looks very mild and possibly very wet.
Best I can do – have a good winter all!
Below is how I think each month will unfold.
| Dec mean temperature | Probability | Rainfall | Probability |
| Very mild | 64% | Wet | 27% |
| Average to mild | 27% | Average | 46% |
| Below average | 9% | Dry | 27% |
| Jan mean temperature | Probability | Rainfall | Probability |
| Very mild | 10% | Wet | 17% |
| Average to mild | 45% | Average | 28% |
| Below average | 45% | Dry | 55% |
| Feb mean temperature | Probability | Rainfall | Probability |
| Very mild | 64% | Wet | 55% |
| Average to mild | 28% | Average | 36% |
| Below average | 8% | Dry | 9% |
It’s been an unusual autumn so far. A very notable lack of sun from the end of October into November was followed by an early cold snap before Storm Bert brought flooding chaos to parts of south Wales, the West Country and elsewhere.
Just before the beginning of every winter I have a crack at predicting what winter will be like; the results often being very mixed.
However, on looking at the stats so far there’s virtually no years that have been similar to this autumn; the one year being 1968.
1968, looking back at reanalyis charts, swung from mild to cold with snow on Christmas Day. The Weather Outlook mentions the conditions on the 25th.
Though the odds are very long at this stage the 850mb chart for 1968 is not beyond the realms of possibilities given the recent synoptic patterns. And if not the 25th I would suggest that a cold snap between Christmas and New Year is a better chance than evens this year.
1968 was the year Bing Crosby sung an alternative intro to White Christmas while marooned in a sunny California.
The sun is shining, the grass is green;
the orange and palm trees sway.
There’s never been such a day
in Beverly Hills, LA.
But it’s December 24th ,
and I long to be up north!
Though we think of snow at Christmas in London it is very rare. And has often been rare been since Victorian times.
Today marks the 866th consecutive day that the rolling 365-day mean has been above 12C, a level that is nearly a degree above the average annual mean temperature for this region.
The next longest period, back to 1960, was 499 days starting on June 9th 2003.
The graph below shows that since around 2015 this 23,644 day period has been stuck in a high rut.
Looking at months on their own it has now been over 20 since this station recorded a month around a degree cooler than average.
This September is looking like it will be yet another milder than average month. If the mean for 2024 finishes above the level of 12C it will be the third 12C year in a row!
Prior to this an annual mean of 12C has been recorded on only 11 occasions since 1960: 1989, 1997, 1999, 2002, 2003, 2011, 2014, 2018, 2020, 2022, 2023 .
This September has seen a lot of convective activity with three days of thunder, already more than the whole of meteorological summer.
The first storms arrived during the early hours of the 8th. Lots of thunder and lightning though only 7.1mm of rain. Further storms bubbled up at 1200 and 1720 with 9.8mm of rain.
Both the 11th and 12th have seen further thunderstorms develop with hail recorded though rain amounts were low; with 0.4mm and 0.6mm recorded respectively.
Here’s a timelapse of cloud activity on the 8th.
The mean for July in east London was 18.4C, 0.1C below the 1981-2010 average and the coolest for 12 years.
Rainfall of 67.1mm was 154% of average, 3mm less than last July. Sunshine at 177.3 hours was 92% of average. Duller than average but not as dull as last July.
A largely uneventful month with an absence of thunder and lightning.
As thought months ago with ENSO moving toward neutral August should be the month with the best chance of any heat records being broken.
A look at the mean temperature shows how much the climate has warmed since the period 1961-90. Though the mean last month was 1.3C down on the previous 10 years it was actually 0.7C warmer than 1961-90.
9am air pressure was largely below average until the final third of the month, coinciding with the arrival of more summer-like weather.
Here’s a few extremes for the month of August across the capital.
The average maxima in Wanstead so far this summer is 22C, some 0.8C higher than in 1990 – the year an August heatwave saw the UK’s max record broken with 37C in Cheltenham. Media at the time said: “I wonder if the UK will ever see 100F?
The temperature in Wanstead on August 3rd reached 35.8C, my station notes for the day say: ‘dry, sunny and very, very hot’.
Will we see a similar heatwave next month? The weather models tonight suggest not, a flat westerly flow keeping any extreme heat in Iberia.
However, in keeping with summers that occur after an El Nino event, the core of any heat usually happens in late summer – August into September.
With the El Niño–Southern Oscillation (ENSO) trending toward neutral I thought it would be interesting to see how east London’s climate has been affected over the past year.
Using the 12-month rolling mean for this station the difference is an increase of 0.24C. The increase in rainfall, using the 12-month rolling average, is more stark with an increase of 100.9mm.
I had a look at all other El Nino events back to the early 1960s. Some 5 of 7 events saw an increase in the rolling average mean.
The 12-month rolling average rainfall similarly saw an increase in 5 of the 7 events.
The most notable event was May 1997 to May 1998 which saw the temperature increase by 1.67C and a massive increase in rainfall of nearly 300mm.
The mean for June in east London was 16.2C, 0.2C warmer than average though the coolest 6th month for 11 years. So yet another warm month – it is now 18 months since we saw a below average one.
Rainfall was on the low side, just 15mm was 29% of average, the driest June for 6 years and 20th driest locally since 1797. Today also moves us into meteorological drought territory – 15 days since there was last measurable rain (>0.2mm)
Sunshine at 204.6hrs was 115% of average, the dullest for 3 years.
The most notable day was probably the 15th with thunder and lightning and a heavy shower at 1230-1300. Further moderate showers in the afternoon.
So, far from being the ‘crap summer’ some are portraying it summer 2024 so far is pretty average here.
More of the same for July. Perhaps a couple of hot days but any prolonged heat staying to our south?
As thought months ago with ENSO moving toward neutral August should be the month with the best chance of any heat records being broken?
Here’s a few extremes for the month of July across the capital.
It’s been a wet winter so far. Some 177mm has fallen in Wanstead – already 122 per cent more what falls in an average winter.
But the amount pales into comparison with the Lake District. Since December 1st 1360mm has fallen at Honister, a station close to Seathwaite which proudly proclaims itself as ‘England’s wettest place’.
Over a calendar year the area usually sees 5.6 times the amount of rainfall of London. However, this winter the total of 1360mm makes it 7.7 times wetter! A testament to just how persistent the SW’ly airstreams have been this season. And a reminder that the Lake District is the called the Lake District for a reason.
Data from the excellent Starlings Roost Weather.
Wanstead Meteo 
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