June 2023: Daily UK Maximum Temperature Records Tumble

It seems that records are now broken in any spell of hot weather. This year one particularly notable daily UK maximum temperature record was broken. Until this year, 13th June was the only date in the meteorological summer (June through August) when 30C had not been exceeded in the UK. Not any more.

In fact. a quick look at TORRO shows that temperatures in excess of 30C have now been recorded in the UK on every date from 27th May through 17th September.

Here are the recent 2023 records:

DateOld record maximum temp. (C), location and year2023 maximum temp. (C) and location
10th June31.7, Maldon, 197032.2, Chertsey Abbey Mead
11th June31.1, Cambridge, 190032.0, Kew Gardens
12th June31.4, Heathrow, 2006 (TWKS gives only 31.0, but I’m taking the TORRO figure)31.3, Rasthorne
13th June29.2, Kelso, 1994 (28.3, Earls Colne, 1948, TWKS)30.8, Porthmadog
Table 1: Daily UK Maximum Temperature Records from TORRO and The Wrong Kind of Snow (2007) (TWKS), 2023 data from Met Office, current records in bold.

None of these are what I call “date” records, that is, the hottest temperature so early in the year. Notably, 34.4C was recorded at Waddington, Lincolnshire on 3rd June 1947. This suggests that, with global warming, temperatures in excess of 35C are now very likely possible over the 10th-13th June period (if not earlier). I expect we’ll see such heat sometime in the next decade or so.

The recent heatwave was reportedly caused by a humid, maritime air mass, rather than a plume from North Africa via Spain and France, such as caused the record temperatures in 2022. I don’t have data, but recent weather conditions don’t seem to me to have been that unusual. Perhaps such weather has occurred at this time in June tens of times over the 150 or so years being compared.

This suggests that what we have experienced this year was not exceptional – just hotter because of global warming – yet still broke 3 daily records. Remember, if daily records were broken randomly – as would be expected in a constant climate – we’d expect on average between 2 and 3 each year (that’s 365 divided by 150).

So we’ve already broken more daily records this year than would be expected without global warming.