The latest weather buzz

Weather updates from site founder Brian Gaze that keep you in the know.

Hottest day of the year

Published 2nd September, 10:22

The meteorological Autumn has now started but in the coming days there will be an increasingly summery theme to the weather. High pressure will bring settled conditions and rising temperatures. In fact, computer models are suggesting anomalous warmth for the time of the year.

Hottest day of the year next week?

The joint hottest days in the UK so far this year were 10th and 25th June when values of 32.2C were reached at Chertsey, Surrey and Coningsby, Lincolnshire. By the standards of recent years that's not particularly hot and there is a possibility that next week could see even higher temperatures.

The chart below shows the temperatures being forecast by a recent GFS computer model run at 15:00 GMT, Wednesday 6th September. Maximums of 33C are indicated at a number of points in eastern England. Therefore, if it is correct a new hottest day of the year will be recorded.

ff

It's worth noting that there is uncertainty at this range in terms of:

1) Which will be the hottest day of next week? One of Tuesday, Wednesday or Thursday appears to be the most likely.

2) How high will temperatures climb? At this time of the year the days are significantly shorter than in June or July, so there is less time for solar heating at the ground level, despite upper air temperatures being at truly exceptional levels.

Nonetheless, more and more computer model runs are showing that temperatures could peak at over 30C. The chance of exceeding 32.2C is growing.

Years when September produced the hottest day

The hottest day of the year isn't often recorded in September, but it has happened a number of times before. The most recent example was in 2016 when 34.4C was reached at Gravesend, Kent on 13th September.

Looking further back, these are the years in the 20th Century when it happened.

1962 27.8C Writtle, Essex 3rd September
1954 30.6C Camden Square, London 1st September
1929 32.2C Camden Square, London , Margate 31st August; Newport, Isle of Wight 5th September
1926 32.2 Camden Square, 19th September
1919 32.2 Raunds, 11th September
1906 35.6 Bawtry,  Yorkshire, 1st September

(Data from Trevor Harley's excellent website) 

PS: Look at that value from 1962. To imagine a year when the maximum temperature recorded in the UK was 27.8C is like the current generation trying to imagine a time when the Internet didn't exist!