Category Archives: Heathrow weather

Climate of London, Heathrow weather, London weather, UK climatology, Weather

July 2019: a new Tmax record

August 2, 2019 wansteadmeteo 1 Comment

July 2019 saw the month’s daily maximum record broken on the 25th with a high of 36.8C, The reading beat the previous record set on July 1st 2015 by 0.8C and was the second highest reading recorded in this area. Cloud that drifted in mid afternoon put paid to any chance of all-time record though Cambridge, further north, managed to break the UK record with a reading of 38.7C. This temperature set in the Botanic Gardens beat the previous record of 38.5C set in Brogdale, Kent, in 2003.

Brogdale

Cambridge

Although it has been mentioned that the Cambridge site appears to be overdeveloped it meets the WMO standard and the Met Office are happy with the record.

Compared with 2003 the heat this time was far more widespread and further north, with many stations recording higher values than 2003, as shown by these 24 hours to 6pm readings below.

In 2003 some 44 stations recorded 30C or above whereas this year some 67 reached 30C or higher.

Though the heat was record breaking it was much shorter lived than 2003. Like last month and July 2015 the 9-day temperature trace is far more ‘pointed’ – perhaps a symptom of the changing behaviour of the jet stream.

Overall the monthly mean finished 19.9C, that’s 1.4C above average though 1.8C cooler than last July – the warmest month on record.

Rainfall at 61.5mm, was 141 per cent of average, the wettest for 2 years. Sunshine, at 165hrs, is 85 per cent of average and well down on last July’s 273hrs.

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

‘Feels like’ maxima.

June 1981-2019 maximum anomalies

The 12 month rolling rainfall total is…

Summary for July 2019

Temperature (°C):

Mean (1 minute) 19.8

Mean (min+max) 19.9

Mean Minimum 14.7

Mean Maximum 25.1

Minimum 9.2 day 03

Maximum 36.8 day 25

Highest Minimum 19.6 day 23

Lowest Maximum 19.5 day 27

Air frosts 0

Rainfall (mm):

Total for month 61.5

Wettest day 20.6 day 19

High rain rate 16.1 day 18

Rain days 10

Dry days 21

Wind (mph):

Highest Gust 16.8 day 20

Average Speed 2.2

Wind Run 1664.1 miles

Gale days 0

Pressure (mb):

Maximum 1029.0 day 03

Minimum 1004.8 day 30

Days with snow falling 0

Days with snow lying at 0900 0

Total hours of sunshine 0.0

Heathrow weather, Heatwaves, Holiday weather, London weather, Weather

More anomalous warmth for late May Bank Holiday?

May 21, 2018 wansteadmeteo Leave a comment

Weather models are hinting that this coming bank holiday weekend could be very warm indeed, with one WX Charts animation suggesting that a positive anomaly of 12C could be possible on Monday.

A date record looks a formality and, unless there’s a downgrade, new monthly high temperature records at stations across the south-east look a possibility.

While it looks very warm it is too early to start talking about heatwaves. And, considering the pattern since late February, with hot and cold alternating weekly, a brief return to much cooler conditions at the beginning of June can’t be ruled out.

The British record high temperature for May is 32.8C, reached on two occasions:

Camden Square, London May 22nd 1922. The same station recorded this value again on May 29th 1944, along with Regents Park, Horsham and Tunbridge Wells.

The national date record for the 28th, according to TORRO, is 30.6C at Camden Square.

Locally the highest temperature recorded in this area in May is 32.1C on May 27th 2005. The date record I recorded is 26.5C in 2012.

Heathrow weather, History, London weather

London’s December extremes since 1959

December 1, 2017 wansteadmeteo 2 Comments

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

Probably most notable is how the month in 1978 lurched from being very mild and wet to very cold in under three weeks later, setting up one of the coldest-ever winters.

Screen Shot 2017-12-02 at 12.41.15

dec recs

December Heathrow

Some national UK December values according to TORRO

Hottest: 18.3C Achnashellach – 2nd 1948
Coldest: -27.2C Altnaharra, Highland – 30th 1995
Wettest: 199.1mm Dalness, Highland – 17th 1966

Climatology

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

december maxima.PNG

December minima.PNG

december rainfall.PNG

Heathrow weather, History, London weather

London’s November extremes since 1959

November 3, 2017 wansteadmeteo 3 Comments

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

Probably most notable is how the month in 2010 lurched from being so warm at the start to so cold three weeks later, setting up December to be one of the coldest on record.

Some national UK November values according to TORRO

Hottest: 21.7C Prestatyn, Clwyd – 4th 1946
Coldest: -23.3C Braemar, Grampian – 14th 1919
Wettest: 211.1mm Lluest Wen Reservoir, Rhondda – 11th 1929

November climatology

In terms of climatology November maxima, considering the 1981-2010 average, shows a steady fall until the 15th. And another steady fall to the 22nd before things level off. This would reflect the November singularities; St Martin’s Summer, between 15th and 21st, peaking on the 18th, occurs in 66 per cent of years. The Early December storms singularity can arrive this month, on the 24th, the air off the Atlantic raising the mean temperature.

The average rainfall graphic shows that downpour amounts are variable through the month. A tendency for dry weather around the 15th reflects the St Martin’s Summer singularity.

This graphic shows the average 9am air pressure in November since 2013.

Heathrow weather, Heatwaves, History, London weather, Weather

Phew! What a scorcher…

July 6, 2017 wansteadmeteo 2 Comments

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!