Temperatures could hit 28C in London on Friday in what is expected to be the hottest day of the year so far, following an unusually cool May.
It has been colder than average for most after temperatures dropped in the first week of the month, the Met Office said.
The warm weather returning to England and Wales on Friday is predicted to linger into next week.
Clouds and thundery showers could hinder Saturday’s heat but if they do not appear then temperatures could exceed Friday’s.
Heard it's warming up?
— Met Office (@metoffice) May 19, 2026
Temperatures are on the rise later in the week and after the recent chilly spell it will feel markedly warmer📈
It won't be entirely dry; thunderstorms are possible on Saturday - but it will be a fine and warm long weekend for the vast majority🌤️🌡️ pic.twitter.com/zJzjfv5GEE
A heatwave in the capital would then be possible by Sunday, Met Office operational meteorologist Niamh Murray said.
The heatwave threshold for London at this time of year is 28C for three consecutive days in the same location.
Ms Murray said: “If temperatures hold up on Saturday, we are expected to keep high pressure around into at least the first half of next week, so there is a potential that we may see those thresholds reached by the time we get to Sunday but… it’s not 100% certain on that yet.”
The contrast with the recent cool spell will make the weekend feel much warmer, she added.
Most of England and Wales, as well as parts of Scotland, will see above average temperatures.
The east coast could see mid to high 20Cs, while Wales and western parts of the north of England may reach 25C.
The hottest weather will be in the south-east, particularly around London, and potentially towards East Anglia.
UK-wide highs for this time of year are 15.5C and recent temperatures have peaked at about 14C.
The hottest day of the year so far was 26.6C in Kew Gardens, west London, on April 8.
Further showers are forecast on Wednesday though they will be lighter and more isolated, Ms Murray said.
Thursday will start cloudy for everybody with some rain in Wales and parts of north-west England.
The weather will brighten for many by the afternoon as the clouds break up, particularly in the south.
