A yellow thunderstorm warning is in place for London on Monday, with temperatures set to stay in the high 20s throughout the week.
The Met Office has issued the alert for the capital and much of southern England from midday to 9pm, warning people should be conscious of the potential for sudden flooding and transport difficulties.
It has also issued similar warnings for parts of Scotland, Northern Ireland, the Midlands and most of Wales.
It comes after a weekend of scorching temperatures and heavy rainfall.
The mercury hit 32C at Kew Gardens in south-west London on Sunday, and much of the UK was hotter than Monaco and the French riviera where temperatures languished in the low 20s.
However, temperatures fell just short of this year’s record high of 32.2C which was reached on Saturday.
A total of 28.6mm of rain fell in Charlwood, Surrey, on Sunday afternoon, which is almost half the average for the whole month of June.
A yellow warning for rain covering southern parts of England and Wales remains in place until 9am on Monday.
Met Office meteorologist Dan Stroud said: “One or two spots have had quite significant rainfall in a short period.
“On Monday, we’re expecting a fine and hot start, temperatures rising fairly quickly during the course of the morning under strong early summer sunshine and that’s likely to spark a few thundery showers.
“Parts of Wales and England will see 30mm of rain in an hour, 60 to 80mm in some spots.
“North parts of Northern Ireland, south-west Scotland and the Highlands could see 20 to 30mm of rain in an hour during the thunderstorms, and 40 to 50mm in some spots.
“Potentially we are looking at a month’s worth of rain falling.
A rather cloudy start across the south on Monday morning with outbreaks of heavy rain continuing to clear westwards across Wales 🌧️
— Met Office (@metoffice) June 11, 2023
Elsewhere a dry and bright start with temperatures soon rising allowing showers to develop from late morning 🌦️ pic.twitter.com/9fkUt1C7Lf
“The highest temperatures will be around Birmingham and in Wales. It will widely be 24C to 28C on Monday, with some spots sitting at the 30C to 32C mark.
“It will be warmer than Monaco, where it has hit 24.7C on Sunday and is expected to be 22 to 24C on Monday.”
Slightly cooler temperatures are on the way from Tuesday onwards, with Thursday and Friday in the mid-high 20s, the forecaster added.
Mr Stroud said: “We are likely to see the hot weather continue although high pressure is starting to build in.
“That’s going to kill off the showers and moving into next week the temperature will dip slightly to the mid to high 20s.”
The UK Health Security Agency has issued an amber alert for hot weather until 9am on Tuesday in the West Midlands, East Midlands, east of England, South East and South West.
A further yellow alert, which is less serious and says there may be some disruption to services due to weather conditions, is in place for the North East, North West and Yorkshire and Humber regions of England, as well as London.
