London could be hit by a thunderstorm on Saturday with strong winds and heavy rain throughout the day, the Met Office has warned.
Forecasters have issued a yellow weather warning between 9am and 6pm for the south of England and parts of Wales.
The weekend could see more rainfall in just a few hours than fell in the whole of May.
The Met Office said Saturday is expected to be a very showery day, with frequent heavy showers - some thundery - with gusty winds and hail.
Londoners have also been warned of “unseasonably windy conditions” following an unsettled start to the summer.
Up to 40mm of rain could fall over the course of a few hours - more rain than fell in the entire month of May. Met Office data shows England had 32.8mm of rain last month, almost half the month's usual average.
It comes after the UK registered its hottest and sunniest spring since records began in 1884, and the driest for half a century.
⚠️ Yellow weather warning issued ⚠️
— Met Office (@metoffice) June 6, 2025
Thunderstorms across parts of central and southern England and Wales
Saturday 0900 - 1800
Latest info 👉 https://t.co/QwDLMfRBfs
Stay #WeatherAware⚠️ pic.twitter.com/3hGwPKctr1
There could also be a risk of surface-water flooding and hail, which forecasters warn “could lead to challenging driving conditions”.
However, Sunday looks to be drier with highs of 19C (66F) in the capital, before further showers on Monday and Tuesday.
Met Office chief meteorologist Dan Suri said: "Frequent heavy showers and thunderstorms are expected for much of Saturday, before they fade from the west during the mid-to-late afternoon.
"It's possible that 10-15mm of rain could fall in less than an hour, while some places could see 30-40mm of rain over several hours from successive showers and thunderstorms.
"Frequent lightning, hail and strong, gusty winds are also possible."
Mr Suri added that it was difficult to predict where exactly thunderstorms might hit.
In just the first three days of June, there was 10.7mm (0.4ins) of rain — a fifth of the 50.9mm (2ins) of rainfall recorded for the UK during May.
Meteorologist Honor Criswick said the wet weather was due to low pressure.
She said: “At the north of the country this brings in a north-westerly wind, so gradually drags in frontal systems out from the west and south-west, and that leads to some pretty changeable and wet weather at times.”
Met Office spokesman Andrea Bishop said the outlook for the rest of the week would be “changeable”.
She said: “Generally the theme is the continuation of something a bit cooler, a bit breezy at times, and a bit wet at times too.
“We are keeping an eye on a new front which looks like it will move in on Friday night, bringing rain which could be heavy, and possibly thundery at times on Saturday.
“Rainfall totals of 20-30mm are likely in places and, at present, this looks like it will affect the southern half of the UK.
“We are keeping a close eye on this to see how it evolves over the next 24 hours or so.”
Forecasters also said that many parts of the UK are expected to enjoy clear and sunny spells throughout the day.
Next week, temperatures in the capital will rise to above average for the time of year, with highs of 26C (79F) next Wednesday.
