Milder temperatures are set to give way to a burst of “very warm” weather this week, forecasters said.
Sunday got off to a cloudy, rainy start for many, with heavy showers in northern England and southern and eastern Scotland.
But as the rain clears, clouds will remain for most while temperatures remain much cooler than Britons came to expect during the summer’s heatwave.
London and Cardiff will both see highs of 19C, Aberdeen will peak at 12C amid stormy conditions in the wake of Tropical Storm Ernesto, while Belfast will see thermometers rise to 17C.
Sunday night will see low cloud and hill fog in some places, while a light drizzle can be expected for northern parts and Scotland, where temperatures will also be markedly cooler.
Monday is set to bring bright spells as humidity builds slowly through the day. The Met Office said temperatures will feel “very warm” in the south of England.
Forecasters said that Tuesday, Wednesday and Thursday will feel humid throughout the day, with muggy nights predicted.
“Humid for most parts and feeling very warm in any sunshine, with warm nights too,” the Met Office said. “Rain in the northwest will slowly move southeastward Wednesday and Thursday, with fresher conditions following.”
Looking further ahead, forecasters said that Britons can expect “a good deal of dry, bright or sunny weather, especially in the south” while west and northwestern parts will see “thicker cloud and rain”.
“This weather pattern is quite likely to continue [until 1 September], with temperatures probably around normal, but perhaps rather cool in the north and northwest,” the Met Office added.