A milestone in UK climate history

25 Jul 2022 12:42 PM

A new event summary from the Met Office shows that the UK’s recent extreme heat was far more intense and widespread than previous comparable heatwaves. This was the first time 40°C has been recorded in the UK.

A new record daily maximum temperature was provisionally reached on 19 July, with 40.3°C recorded at Coningsby, Lincolnshire, exceeding the previous record by 1.6°C. A total of 46 stations across the UK exceeded the previous UK record of 38.7°C. Many long-running stations with 100+ year records recorded their highest ever temperature, some by extraordinary margins of 3 to 4°C. Records were set overnight too, when Kenley Airfield, Greater London, recorded a new highest minimum temperature of 25.8°C.

New provisional national temperature records were also set for Wales and Scotland. On 18 July, 37.1°C was recorded at Hawarden Airport, Flintshire, while 35.1°C was reached at Floors Castle, Borders on 19 July.

The post-event report from the Met Office shows that the record-breaking temperatures seen as part of the heatwave demonstrate much more widespread and significant heat than previous noteworthy extreme heat events.

Historically significant heat

Temperatures on both 18 and 19 July exceeded 38°C, with only two previous dates exceeding this threshold in Met Office data; 10 August 2003 and 25 July 2019. These four dates: 18 and 19 July 2022, 25 July 2019 and 10 August 2003 are the only occasions when 38°C has been recorded in the UK in observations extending back to the mid-19th century.

Map showing the heat of the UK during previous extreme heat events. The map shows that July 2022's heat was more intense and widespread than previous events.

The Met Office’s Mike Kendon, who produced the review, recently said:

“Temperatures on 18 July were exceptional but they moved 2 to 4°C higher on 19 July, making this date unprecedented in the context of long term climate records.

“What’s particularly notable is how much more widespread the heat was from this event than the previous two occurrences of temperatures in excess of 38°C in the UK. Temperature records tend to get broken by modest amounts and by just a few stations, but the recent heat broke the national record by 1.6°C and across an extensive area of the country from Kent to North Yorkshire and from Suffolk to Warwickshire.

“Even when you factor in the temperatures seen in summer 1976, they didn’t reach anywhere near the levels seen this week, although that was a much more prolonged spell of hot and dry weather.”

The heat resulted in the Met Office issuing its longest-range Amber warning ever, with a lead time of six days and a subsequent Red warning for extreme heat; the first such one to be issued.