Heatwave helps mark fifth warmest July on record

The mid-month heatwave has helped the UK to its joint fifth warmest July on record according to provisional Met Office figures, with Scotland and Northern Ireland recording their third warmest July, in a month where Northern Ireland also broke its all-time high temperature record, exceeding 31C multiple times.  

The mean temperature for July 2021 in the UK was 16.6°C, which put it level with July 1995’s figure, although still some way short of the record figure of 17.8C in 2006. Northern Ireland (16.4° C) and Scotland (15.1°C) saw their third warmest Julys, Wales (16.5°C) its ninth warmest and England (17.5°C) its eleventh warmest.  

A Mean temperature map of the UK for July 2021, showing above average temperatures throughout, especially in western Scotland and Northern Ireland.
July 2021 mean temperature map

While the high mean temperatures were spurred on by the mid-month heatwave, the figure was helped to its elevated position in the standings with notably high night-time temperatures recorded across the month, with the average minimum temperature for the UK putting it at joint-second for the warmest recorded in July, at 12.1°C.  

Of course, most people will remember July 2021 for the heatwave during the middle of the month, which saw the Met Office issue its first ever extreme heat warning. Western areas in particular got the most consistently hot conditions, and Northern Ireland even broke its all-time temperature record with a figure of 31.3°C recorded at Castlederg on 21st *.  

Both Scotland and Northern Ireland had average maximum temperatures for the month in their top 10 ever recorded, with 21.2°C in Northern Ireland being the fifth highest and 19.2°C in Scotland being their sixth highest.  

On a similar theme, Scotland and Northern Ireland were also far drier and sunnier than average for July. Both countries saw 25% more sunshine hours than average, with 175.6 sunshine hours for Scotland, and 175.5 for Northern Ireland. Scotland got 67% (66.4mm) of average rain in the month, while Northern Ireland got just 53% (43.3mm).  

A map of the UK showing average sunshine duration for regions versus the long term average. The map shows many western areas had above average hours of sunshine in the month, especially western Scotland. Eastern areas have closer to average sunshine hours.
July 2021 average sunshine hours map

Despite the dry month for western areas in particular, intense summer downpours affected some areas of the country and resulted in some places exceeding twice their average rainfall for July. The Isle of Wight had its seventh wettest July on record – and its wettest since 1920 – with 115.4mm of rain, while parts of London recorded more than double the average rainfall they’d expect in the month. The localised nature of some of the summer downpours meant there could be some sharp contrasts with, for example, some parts of London receiving much closer to average rainfall. 

A map showing the rainfall across the UK versus the average for July 2021. It shows many southern areas had above average rainfall, while western areas, especially Northern Ireland and western Scotland, had below average rainfall.
July 2021 rainfall amount map

In addition, despite the mid-month heatwave, some unsettled and thundery conditions were in force for much of the second part of the month, which even saw Storm Evert named and sweep across southern areas of England and Wales, bringing with it gusty winds and some persistent rain.  

Tim Legg of the National Climate Information Centre said, “Early July was relatively unsettled, with frequent heavy showers, especially over parts of England. The early subdued temperatures were replaced with a very warm spell for much of the UK as a high pressure system moved in and settled down, resulting in temperatures regularly getting in to the low 30s Celsius by day and remaining warm overnight.  

“The hot spell is largely responsible for the above average temperatures recorded for the UK, with western areas in particular reporting temperatures well above their July averages. This warm period broke down later in the month, bringing with it rain, thunderstorms and even the first storm we’ve named in July when Storm Evert crossed our shores from the 30th.” 

Provisional July 2021Mean temp (°C) Sunshine (hours) Rainfall (mm) 
 Actual Diff from avg (°C)Actual% of avgActual% of avg
UK 16.6 1.5 191.6111  72.5 93
England 17.5 1.2 200.7104 78.3 125
Wales 16.5 1.4 203.4114 79.7 86
Scotland 15.1 1.8 175.6125 66.4 67
N Ireland 16.5 1.9 175.5125 43.3 53

* A provisional temperature of 31.4 C was recorded at Armagh on 22nd July, which did not pass all subsequent verification checks.  

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