Lightning, flashfloods and hail storms flooded tube stations and gridlocked roads in the capital - while the North continued to bask in sunshine.
However, forecasters say this is the “normal” summer weather Londoners used to experience where fierce storms are caused by high temperatures. The recent cooler summers have not seen flashfloods as there hasn't been enough heat to cause them.
And with the heatwave continuing, people should expect more sharp, vicious storms next month as the warm weather creates unsettled conditions.
The Met Office says the localised flooding was caused by convective rain, where the hot weather causes the moisture in the ground to evaporate and rise, forming clouds as it cools and condenses.
In pictures: Flooding hits Hillingdon
Met Office spokesman Daniel Williams said the phenomenon is not unusual in the summer months.
“In the winter we get weather fronts which can bring similar weather to the whole country,” he said.
“Convective rain is much smaller scale and comes in the form of isolated showers, some of which can be only 100 metres across.
“It means that some areas can get really heavy rain while down the road it can be completely dry.”
For example, yesterday in Northolt 43.8mm (1.72in) of rain fell from 1am to 3pm — while across the city in Bexley just 1.6mm (0.63in) of rain was recorded.
Rain is expected to return by Friday lunchtime, with heavy downpours predicted throughout the whole country and lasting until Saturday morning.
The localised flooding was caused by convective rain, where the hot weather causes the moisture in the ground to evaporate and rise, forming clouds as it cools and condenses.
Met Office spokesman Daniel Williams said the phenomenon is not unusual in the summer months.
“In the winter we get weather fronts which can bring similar weather to the whole country,” he said.
“Convective rain is much smaller scale and comes in the form of isolated showers, some of which can be only 100 metres across.
“It means that some areas can get really heavy rain while down the road it can be completely dry.”
