Nearly 20 areas in Cornwall are set for showers on bank holiday Monday, though most will still see sunshine breaking through the clouds.
The Met Office expects Monday (August 31) to be the best weather of the long weekend, after festivalgoers faced rain and mud in plastic ponchos on Saturday and Sunday.
This follows the wettest weekend of the summer so far in the south west, with Bradworthy Common in neighbouring Devon recording 34.2mm of rain in 12 hours on Sunday, more than a third of the average for the county for August.
Met Office senior operational meteorologist Dan Stroud said: “It’s another day of sunny spells and showers, a generally bright but cloudy start with sunny spells in the east, we will have some showers from the get-go in the west and they will become a bit more heavy, the odd rumble of thunder is possible.
“A drier and brighter end to the day. Monday promises to be the best of the three days, still showers around but a lot less than what we’ve seen.
“Tuesday across England and Wales promises to be reasonably fine with some lengthy sunny spells. It’s a different story across Scotland. We've got a band of cloud and rain.
“Wednesday, it changes, it goes downhill, turning cloudy and wet during the course of Wednesday, particularly across Wales and northern England northwards.”
At Reading Festival, music fans wore ponchos and umbrellas and played in the mud after heavy downpours over the weekend. Some were seen throwing mud at each other and splashing in puddles, while others sheltered under plastic ponchos.
Elsewhere, the cricket at Lord’s in London was halted by the rain on Saturday.
The Met Office has previously said the UK is on course for its hottest summer on record after five heatwaves, with temperatures of up to 38.1C recorded in London.
Weather maps show 18 towns in Cornwall will see rain on Monday. They are:
Met Office Forecasts Rain for 18 Cornish Areas on Bank Holiday