Monday was the first time temperatures of over 20C had been reported in winter, breaking a record that had stood since 1998.
It means that parts of Britain have been hotter than holiday destinations such as Ibiza.
The usual average for this time of year is between 7C and 9C (48F).
Temperatures broke the previous day’s record of 20.6C in two other places, the Met Office said.
Porthmadog in north-west Wales hit 20.8C (69.4F) while temperatures of 20.7C were reported in Teddington, south-west London.
In Scotland, the temperature reached 18.3C on 21 February in Aboyne, Aberdeenshire, breaking a record of 17.9C which had stood for more than 120 years.
In Northern Ireland, temperatures reached 15.6C in Castlederg, County Tyrone. The February record of 17.8C was recorded in 1998
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Meanwhile, firefighters have warned the warm weather could lead to a greater risk of outdoor fires.
The warning, from East Sussex Fire and Rescue Service, came after two large fires broke out in Ashdown Forest – the East Sussex forest made famous by AA Milne’s Winnie the Pooh novels.
Dr Friedericke Otto, acting director of the Environmental Change Institute at Oxford University, said people were right to ask themselves whether the record temperatures were being driven by climate change.
“I am very confident to say that there’s an element of climate change in these warm temperatures,” she said.
“But climate change alone is not causing it. You have to have the right weather systems too.”
BBC science editor David Shukman said scientists such as those at the Met Office were usually reluctant to link individual heatwaves, storms or floods directly to climate change without a specific study to prove it.
But he said research had shown that events like last summer’s heatwave were made more likely by the rising levels of carbon dioxide and other greenhouse gases in the atmosphere.