Category Archives: UK rainfall

London’s August extremes since 1959

I’m running out of superlatives for this summer. There has already been 15 days where the temperature has reached or exceeded 30C, two more than 1976!

However, the mean temperature has not been as intense as that classic summer where two heatwaves of five days and four days length were featured during the season. This summer has so far only seen one similar heatwave of 5 days length.

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

august top ten wans

august SJP

august heathrow

Some national UK August values according to TORRO

Hottest: 38.5C Brogdale, near Faversham, Kent – 10th 2003
Coldest: -4.5C Lagganlia, Highland – 21st 1973
Wettest: 238.8 Cannington, Somerset – 18th 1924

In terms of climatology August maxima, considering the 1981-2010 average, shows a fairly steady decrease through the month, though around the 15th there is often a spike before a steady decrease to month’s end. This would reflect the late August winds singularity which occurs every year around the 20th at 67 per cent probability.

august av max

The average rainfall graphic shows that downpour amounts are fairly random from year to year. The driest days are the 15th and the 30th.

aug av rain

 

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July 2018: warmest month on record

July 2018 was the warmest month locally in a record going back to 1797. The mean temperature of 21.7C is 3.2C above the 1981-2010 average and exceeds the previous warmest July (1983) by 0.3C. Indeed, it is the warmest calendar month ever.

jul152018
MODIS image July 15th 2018

Just 16.7mm of rain fell, all of it coming after the 47 day long drought ended with a thunderstorm on the 27th. The amount is 38 per cent of average and is the driest July since 2010 and 7th driest in the local record.

There were 273 hours of sunshine, 142 per cent of average, making it the sunniest for five years and 10th sunniest on record.

As well as many hot days the lack of rainfall was most noticeable with catastrophic results on Wanstead Flats.

The warmest day occurred on the 26th with 34.7C.

The wettest day occurred on the 27th with 7.3mm falling.

 

 

East London: drier than the Sahara desert

This summer has seen less than a millimetre of rain fall across our region, less than some parts of the Sahara desert!

The lack of precipitation has had catastrophic results, not least being a big contributing factor to the huge grass fire that swept through parts of Wanstead Flats at the weekend.

Since May 29th just 0.7mm has fallen in Wanstead, less than the 2.9mm recorded in Bechar, Algeria, and far less than Agadez in Niger which recorded nearly 108mm.

50 days

Of course the fact that the mean temperature of Wanstead over the same period is at least 13C cooler than both Saharan towns means that the dunes won’t be blowing across the Temple any time soon.

The affects of the dry weather can also be seen across the UK in these MODIS images, the lush greens of last year looking much paler and browner.

comparison

 

jul232014
MODIS image July 23rd 2014
jul152015
MODIS image July 15th 2015
jul192016
MODIS image July 19th 2016
jul172017
MODIS image July 17th 2017
jul152018
MODIS image July 15th 2018