Saturday has provisionally become the hottest day of the year so far with 20.9C recorded, the Met Office said.
This is despite the travel chaos caused by Storm Kathleen in many parts of the country, which left thousands of passengers hit by delays after about 140 flights were cancelled amid winds of up to 70mph.
The highest temperature was reached in Santon Downham, Suffolk, on Saturday afternoon, beating the previous daily high of 19.9C on the 28th of January in Achfary, Sutherland.
However, the capital did not reach those heights, despite predictions it would, with a maximum temperature recorded of 19.5C, said a Met Office spokesman.
While London’s sunny weather was not the warmest in the UK, it marked a stark contrast to conditions elsewhere in the UK, with the north west and south west of England among the areas under a ‘yellow’ weather warning for wind.
Although many parts of the country saw above-average temperatures, Met Office forecasters said many areas will have felt colder because of the storm’s strong winds.
A further yellow warning for wind has been issued for north-west Scotland on Sunday between 9am and 3pm.
Also among the disruption caused by Storm Kathleen was the cancellation of ferries between Larne in Northern Ireland and Cairnryan in Scotland until late Saturday afternoon.
Meanwhile, Saturday evening’s EPCR Challenge Cup rugby match between Edinburgh Rugby and Aviron Bayonnais was moved due to windy conditions.
In Ireland, around 34,000 people were left without electricity, mainly concentrated in Mayo, Galway, Kerry and Cork. Some exposed and coastal areas were being warned to expect gusts reaching higher speeds of up to 70mph.
Met Office meteorologist Ellie Glaisyer said Storm Kathleen will ease on Sunday evening, but another weather system towards the South West will replace it.
She said: "Outbreaks of rain through Monday will mainly affect western parts of the UK. As we go through the day into Tuesday we're likely to see the strongest wind across the south-west of the UK.
"It's coming relatively quickly after Storm Kathleen.
"It's not out of the question that a warning could be issued but I wouldn't like to say yet."
Storm Kathleen, named by the Irish meteorological service Met Eireann, is the 11th named storm in eight months.
