Britain is expected to bask in its hottest days of the year so far, with Wednesday predicted to be even hotter.
Temperatures will reach a high of 26C (78F) on Tuesday before possibly hitting 30C (86F) on Wednesday according to MeteoGroup, the weather division of the Press Association.
But high humidity means many areas could see rain and thunderstorms on Wednesday morning and evening and sunshine struggling to break through the cloud.
Brendan Jones, senior forecaster at MeteoGroup, said the weather was being carried by warm air coming up from the Continent, with Germany, France and the Low Countries seeing temperatures soar past 30C (86F) in the past few days.
"It does look as if today (Tuesday) and tomorrow are going to be very warm," he said. "I think today will be the hottest day of the year and tomorrow will break that again."
Temperatures should be high across England and Wales, with the South East seeing the highest temperatures, he said.
Because of the large amount of cloud, they are likely to hit a high of around 28C (82F) tomorrow, but any areas lucky enough to have sunshine all day may see temperatures hitting 29C (84F) or 30C (86F).
Further north, temperatures will remain lower, and they will fall back to the low 20Cs from Thursday, Mr Jones said.
The welcome warm blast follows what the Met Office said was the coldest spring since 1962, with a mean temperature across March, April and May of 6C (43F), 1.7C below the long-term average.