BBC Weather has forecast rain or showers on six consecutive days in London, from Wednesday, August 26, through Monday, August 31, marking a sharp shift after the city experienced five official heatwaves this summer.
The week will start predominantly dry, with temperatures slightly above average and peaking at 25°C before rain arrives on Tuesday. The unsettled spell then takes hold, with the BBC forecast showing thundery downpours, heavy rain, and intermittent sunshine across the period.
Wednesday brings thundery start, then sunshine
Wednesday is expected to bring early thundery downpours before sunshine returns later in the day. Temperatures could reach 26°C, making it the warmest day of the week. Thursday is forecast to be another unsettled day, with further heavy rain and thunderstorms interspersed with occasional sunshine, with highs around 24°C.
Friday will bring some sunny spells, but a band of rain is forecast to move in from the west, with temperatures falling to around 22°C. The wet weather is expected to continue into the weekend, with rain and showers on Saturday and Sunday, with temperatures reaching around 23°C and 22°C respectively.
Met Office warns of heavy rain threat
The Met Office has warned that the "heavy rain threat increases" from Wednesday, with showers and outbreaks of rain becoming increasingly widespread. While Wednesday will start with light showers and gentle breezes, the Met Office has predicted that Thursday, August 27, will have thundery showers and light winds from around 3am.
Met Office Deputy Chief Forecaster, Mark Sidaway, said: "While many areas will see dry and increasingly warm conditions at the start of the week, attention is turning to the potential for heavy rain and thunderstorms from Wednesday onwards."
"As warmer and more humid air moves north across the UK, there is an increasing likelihood of some heavy rain developing. Some places could see 20 to 30mm of rain in just a few hours, while there is also the potential for higher totals where thunderstorms repeatedly affect the same locations."
Weekend and Monday remain unsettled
Monday is also expected to remain unsettled, with rain or showers and some brighter spells. Temperatures are forecast to reach around 23°C, with an overnight low of 13°C. The unsettled run follows a warmer Wednesday, when temperatures could reach 26°C.
The BBC's 7-day forecast for London shows Tuesday, August 25, as cloudy with sunny spells, with a high of 24°C and low of 16°C. Wednesday, August 26, brings thundery showers and sunny spells, with a high of 26°C and low of 17°C. Thursday, August 27, has heavy rain and thunderstorms with occasional sunshine, with a high of 24°C and low of 15°C.
Friday, August 28, sees sunny spells followed by rain moving in from the west, with a high of 22°C and low of 15°C. Saturday, August 29, and Sunday, August 30, both bring rain and showers, with highs of 23°C and 22°C, and lows of 15°C and 14°C respectively. Monday, August 31, has sunny spells with showers, with a high of 23°C and low of 13°C.
Sidaway added: "The detail of which areas will see the heaviest rainfall is still uncertain, so stay up to date with the forecast this week to keep updated on the increasing risk of impactful weather during the latter part of the week."
