New May daily air temperature records have been verified through a stringent quality assurance process, confirming the figures meet strict national and international standards.
Late May saw an unprecedented heatwave for much of the UK, with the highest maximum and minimum temperature May records broken for both the UK and Wales, as well as a new highest May minimum temperature record for Northern Ireland.
The figures were originally reported as ‘provisional’ as new national monthly records undergo a rigorous validation process before being officially inducted into the meteorological records books.
This verification process includes a site inspection and check of the equipment used to measure the temperature across a network of stations that are managed to ensure they remain as stable and consistent as possible.
In order for a value to be treated as an official national record, the Met Office follows national and international best practice and guidance. If stations or instruments don’t meet the required standards, the provisional figure would be rejected as an official national record.
Met Office Head of Observations Operations Elizabeth Sykes said: “Verifying temperature records is an important part of the process for inducting new figures into the record books.
“While all weather data is subject to stringent national and international guidance and criteria, the extra verification steps for records helps us maintain our confidence and authority in the figures quoted.
“We have dedicated teams working across the UK to maintain our sites and instruments and help with the verification to keep Met Office figures to the high standards we all expect.”
As well as checking the site and the measuring equipment in person, the verification process includes a minute-by-minute analysis of the figures reported and a meteorological summary of the day’s conditions to check alignment in what was meteorologically possible and what was observed.
In addition, data is compared with nearby readings to ensure its feasibility and that it is representative of what occurred on the day.
The new May daily temperature records are now official and listed below:
- Highest UK May daily maximum temperature: 26 May 2026, 35.1°C, Kew Gardens.
- Highest UK May daily minimum temperature: 27 May 2026, 21.4°C, Camborne.
- Highest Wales May daily maximum temperature: 26 May 2026, 32.6°C, Cardiff Bute Park.
- Highest Wales May daily minimum temperature: 26 May 2026, 18.9°C, Aberdaron.
- Highest Northern Ireland May daily minimum temperature: 28 May 2026, 15.9°C, Killowen.
A new Met Office event summary states that, taking into account the time of year being spring and not summer, this heatwave was one of the UK’s most extreme high temperature events in our observational records.
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