June 2023 has been the hottest June since records began at Lancaster University’s Hazelrigg weather station.

The average maximum daily temperature for June 2023 was 21.5C, compared to 20.9C in June 1970, the previous hottest June recorded at Hazelrigg.

Scientists at Hazelrigg also recorded the single hottest June day since records began at the site.

Monday June 12, 2023 saw temperatures hit 30.1C, topping the previous records of 28.4C in June 2020 and 2000, by 1.7C.

Dr James Heath, from Lancaster Environment Centre said: “In terms of the temperatures, it’s worth noting that June 1970 didn’t see anything quite like the extremes that we saw this year – instead the temperatures were more consistently in the low to mid 20s for a substantial period, with a couple of hot days topping 27C.

“This year, for the first week or so, the warm temperatures were purely as a result of the long periods of strong sunshine under persistent high pressure.

“Then, very warm air from the south arrived, giving us the record-breaking 30.1 C on June 12 – and the week from June 10 saw temperatures over 25C (the Met Office’s ‘heatwave’ threshold for this region) on six days out of the seven.

“Though the second half of the month saw much less sunshine, the warm air remained – particularly noticeable at night, with a minimum of 18.4 C on June 25.

“The only day that saw a maximum temperature below the long-term average was Friday June 30.”

The total monthly sunshine hours for June have also beaten the previous record set in 1975.

James added: “Although a calendar month seems quite an arbitrary period of time, we can see quite clearly that incidences of high temperatures / heatwave conditions are becoming more frequent and extreme – therefore it is increasingly likely that these monthly records will be broken more frequently.”

Hazelrigg is a UK Met. Office climatological station where daily measurements of temperature, rainfall and sunshine etc have been taken there since 1976, with a further 10-years of data collected before that on the university’s Bailrigg campus.

Temperatures (average daily Max, Min, °C)

2023: Max 21.5; Min 12.3.

Average to 2022: Max 17.1; Min 10.0.

Previous warmest (1970): Max 20.9; Min 11.5.

Sunshine (monthly total)

2023: 291.9 hours

Average to 2022: 182.0 hours

Previous sunniest (1975): 285.4

Rainfall

The amount of rain measured at Hazelrigg during June was 61.9 mm. Although not far off the average (74.4), this was not enough to make up the deficit from the very dry second half of May / first half of June – “especially as the first substantial rain on June 18 would have fallen onto extremely dry, hard ground so a lot would have been lost as runoff directly into rivers,” added Dr Heath.