The world-famous British gloomy weather is going through a transition, and climate change might be behind it. May was the sunniest calendar month on record in the UK, continuing a trend that saw the sunniest British spring thus far, according to data from the Met Office.

Following a drenching winter with record rain, the UK had 266 hours of sunshine in May – besting the previous record of 265 hours from June 1957. A record was also broken in spring, with 626 hours of sun, compared to the 555 hours registered in 1948, the previous record-breaking year for sunny days.

This sudden switch from extremely wet to extremely dry surprised meteorologists, claiming this doesn’t seem like British weather. The UK gets on average 436 hours of sun between March and May. Since 1929, only 10 years had more than 500 hours – with none seeing more than 555 hours.

“We’ve swung from a really unsettled spell with weather systems coming in off the Atlantic to a very, very settled spell,” Professor Liz Bentley, chief executive of the Royal Meteorological Society, told BBC. “It’s unprecedented to see such a swing from one extreme to the other in such a short space of time. That’s what concerns me.”

Warm weather at the end of May offset cooler conditions earlier in the month, the Met office reported, adding that the month was warmer than average but not exceptionally so. It has been the driest May in England and second driest in Wales with 9.6mm and 14.3mm, respectively.

Is it due to climate change?

The Met Office said this is not an indicator of the future, because the jet stream might behave differently. Meteorologists believe man-made climate change may be implicated but said it is too soon to tell. The rapid heating of the Arctic may be influencing the jet stream, although that is not proven.

Professor Joe Smith, chief executive of the Royal Geographical Society, told the BBC: “In a wider context it’s a signal of the increasing unpredictability of the UK’s climate. The fact remains that bold early actions to slash emissions can still cut the larger risks associated with climate change in the UK and around the world.”

Weather is part of the UK identity, with more than nine in ten that have talked about it in the last six hours, according to a survey. Britain’s geography has made its weather mild, changeable, and famously unpredictable. The variability means residents never know quite what to expect

Climate change is causing warming across the UK, according to research by the Met Office. All of the UK’s ten warmest years on record have happened since 2002. Heatwaves are now 30 times more likely to happen due to climate change. Winters are projected to become warmer and wetter on average.