The bank holiday weekend will get off to a wet and thundery start for one half of the UK, but the other half will enjoy sunshine and dry skies.
The weather divide will see the east lose out, with heavy downpours and a risk of flooding throughout the day, particularly in the north, dampening the Bank Holiday spirit. The rain has already set in overnight.
Meanwhile the west of the UK will able to dust off their BBQs and enjoy dry, sunny spells with just a small chance of the odd light shower.
The weather will gradually improve in the east on Sunday before the whole country will finally be able to enjoy sunny weather together on Bank Holiday Monday, with predicted highs of 26C (78.8F).
Tom Tobler, a forecaster for MeteoGroup, the weather division of the Press Association, said: "There will be quite a clear east-west split over the weekend.
"There will be a lot of heavy rain about, confined mainly to the east of the UK. In contrast the west will be mainly dry, with just the off shower.
"The rain will be the heaviest in the south-east and the north, with a risk of flooding in areas which see thunderstorms. It's a gradually improving picture on Sunday, but Monday will be the best day of the three-day weekend.
"The east will catch up and the majority of the UK will enjoy sunny, dry weather with highs of 26C."
Tens of thousands of campers at this weekend's Reading and Leeds festival will be waking up to a muddy start.
The sister rock festivals, which gather for three days over the Bank Holiday, will both see heavy downpours, but Leeds will be the worst off before sunshine moves over both sites on Monday.