The Met Office warned “persistent and heavy” rain is predicted to fall on Brits today.
Northern and eastern England will face bouts of heavy rain this morning with the risk of flooding in western Scotland.
A yellow weather warning for rain has been issued for parts of central and northern England, while a similar alert for thunderstorms is in place in Scotland.
There are 10 flood warnings in place across the UK – from North Yorkshire, Lancashire and the West Midlands – with the Environment Agency saying local flooding was possible due to the thunderstorms and outbreaks of heavy rain.
Commuters might see travel disruptions if the weather conditions worsen but temperatures will remain in the high teens.
A Met Office spokesman said: “Rain will be persistent and heavy in places across parts of central, northern and eastern England and north-east Wales at first on Wednesday.
“During the day rain may turn more showery in places but with a higher chance of thunderstorms by afternoon.
“Some parts of northern England could see as much as 40-60mm of rain through Wednesday, while thunderstorms could produce as much as 30-40 mm in 1-2 hours.”
The miserable weather is a continuation of Tuesday, where hailstones the size of sweets fell in some areas and others having a month’s worth of rain in four hours.
North Yorkshire was pounded by hailstones as a summer storm swept through the county, while Malham Tarn in the Yorkshire Dales had 82.2mm of rain in 24 hours, the majority in the space of four hours.
The monthly average in the area for this time of year is 89mm.