Britain has enjoyed the warmest new year on record as temperatures rose above 16C.
The Met Office said temperatures increased overnight to reach 16.5C in Bala, Gwynedd, north Wales.
A spokesperson said: “This makes New Year’s Eve 2021 provisionally the warmest on record.
“Despite this value occurring overnight, we use the 0900-0900 time period for historical records.”
It could also be the hottest New Year’s Day on record as the Met Office said it was awaiting confirmation that 16.2C had been reached in St James’s Park, central London.
The current New Year’s Day record temperature was 15.6C recorded in Bude, Cornwall, in 1916.
Met Office forecaster Dan Stroud urged people to “make the most of the warmth because a change is on the way as we go into the early part of next week”.
Daytime temperatures are expected to plunge to as low as 3C in Edinburgh by Tuesday and 7C in London and Cardiff.
He said: “We are going to be losing the sub-tropical air flow and replacing it with some things from the north.
“Temperatures will definitely go back to average, with a return of frost and some snow in the forecast across north areas and across the hills.”
The warm start to the new year follows a mild December and record-breaking temperatures during the day on New Year’s Eve.
Friday saw temperatures reach 15.8C in Merryfield in Somerset and Nantwich in Cheshire, which beat the previous record of 14.8C.
The balmier-than-usual start to the year saw people happily take part in traditional New Year’s Day swims across the country, including at Derby Pool, New Brighton, Wirral.
Met Office forecaster Craig Snell said the average temperature in December and the beginning of January is usually around 7C or 8C, with the warmer weather due to a south-westerly wind making its way across the country.
The higher temperatures are usually localised, but “plenty of places” have seen highs of 15C over December, he said.
On Friday, Somerset House in London confirmed it would be closing its ice rink on New Year’s Day due to warmer temperatures.
A spokesperson for the attraction tweeted: “Skate update: Due to the effect of the on-going warm temperatures on the quality of the ice, we have had to make the difficult decision to also close our ice rink on 1 January.”