The Met Office has said that warmer weather is on the way, but for Scotland, Northern Ireland and Northern England will see heavy rain over the next few days.
A yellow warning has been issued for these areas for rain which comes into force from around midday on Friday.
By the weekend the weather will turn unseasonably warm is some areas of the UK.
Meteorologist Alex Burkill said: “The jet steam is going to push its way northwards ahead of the weekend, which will allow for some very warm air to come in from the south.
“As we go into the weekend frontal systems will remain trailing across Scotland as this warm air moves into the south. For many further south it will be a fine, dry day on Saturday with temperatures getting to highs of around 25C, which is unusually warm for the time of year.
“By Sunday, it’ll be a more widely dry and sunny day for many. Highs or around 26C or even 27C in isolated spots is possible.”
RNLI National Water Safety Partner, Samantha Hughes, said: “With warm weather forecasted, we are likely to see people visiting the coast and inland waterways. As it is outside of the summer season, not everyone will be able to access a lifeguarded beach so we’d like to remind people what to do if they find themselves struggling in the water.
“Remember to float to live. Tilt your head back with your ears submerged, try to relax and breathe normally, move your hands to help you stay afloat. When it is safe, then swim to safety or call for help. If you see someone else in danger at the coast, please call 999 or 112 and ask for the Coastguard.”