Lancaster scientists measure record-breaking spring weather

Sunshine totals had exceeded the previous record – set during the lockdown of 2020 – for the whole of spring (which counts as March, April and May) by May 20.

By the end of spring sunshine totals were more than one-and-a-half times the average and the site experienced 66 hours more sunshine than in 2020.

May itself was by far the sunniest May on record, with 310.9 hours, not only exceeding the previous record of 279 hours set in May 1980, but making it the sunniest of any calendar month ever recorded at Hazelrigg.

The previous sunniest month recorded at the site was June 2023, which saw 291.9 hours of sunshine.

Sunniest springs measured at Hazelrigg:

2025: 686.2 hours of sunshine

2020: 620.2 hours

1980: 566.0 hours

1974: 533.7 hours

2007: 529.6 hours

Located on a hill above Lancaster University’s campus, Hazelrigg is a UK Met Office climatological station where scientists from Lancaster University have been taking daily measurements of temperature, rainfall and sunshine etc since 1976, with a further 10 years of data collected before that on the university’s Bailrigg campus.

Scientists at the site say the sunny conditions were partly responsible for the record-breaking temperatures, with daily maximum temperatures for the season nearly 1.5C above the previous record warmest spring.

Dr James Heath, from Lancaster Environment Centre, said: “The settled, clear conditions led to some fairly chilly nights – there were nine nights with a grass frost during May – but the overall mean average spring temperatures were still well above the previous record, set only last year.

“The other factor here is the general warming trend – of the 10 warmest springs recorded at Hazelrigg, five have been in the 2020s, and the Met Office recently published data showing that spring is the fastest warming of the four seasons in the UK.”

Warmest springs measured at Hazelrigg:

2025: 10.48C mean average temperature

2024: 10.17C

2017: 9.72C

2022: 9.72C

2014: 9.70C

It was also the third driest spring recorded at the site. Rainfall totals ending up at just over half of average with the spring being the driest since 1990. March had only 33% of its average rainfall making it the driest March on record; April had just 23% of its average rainfall.

Dr Heath said “The site experienced 31 consecutive days with no measurable rainfall at all between the Easter and late May bank holidays, the end of May saw the monthly average rain falling in just one week.

"There was more over that bank holiday weekend than the whole of the rest of the spring up to that point.”

Driest springs measured at Hazelrigg:

1984: 84.9mm of rain

1990: 107mm

2025: 108mm

1974: 118.7mm

2010: 125.5mm

Dr Heath says the reason behind all of this is that up until the last week of May, with brief interruptions in late March and over Easter, spring 2025 has been dominated by the presence of large, ‘blocking’ high pressure systems sitting near to or over the UK.

"These systems divert the usual westerly flow (the jet stream high in the atmosphere and the associated Atlantic, rain-bearing low pressure systems that normally give us rain) north and/or south of the UK,” he said.

“High pressure is essentially an area with air converging in the upper troposphere, which is the part of the atmosphere where all our weather ‘happens’.

"There is more weight of air above us, and the only place it can go is down – warming, drying, and suppressing cloud formation in the process.

“It’s not at all unusual to have such a spell of weather in spring, but its persistence recently has been remarkable.”