Following a week of sunshine, temperatures could hit 26C tomorrow in eastern parts of England, with the rest of the UK expected to reach at least the high teens or low 20s.
Emma Smith, a Met Office meteorologist, said: “As we go into this afternoon and evening, the temperature is starting to get a bit warmer.
“In eastern areas, we are likely to see 26C as a maximum temperature - this time of year we should have a maximum of 18C or 19C in London.”
Across Yorkshire it is predicted to be a little cooler than that but still over the 20C mark.
Highs of 22C and 21C are forecast for York and Leeds tomorrow and Sunday and it might even make 23C in Sheffield.
Meanwhile, on the North Yorkshire coast the sea breeze will take the edge off the temperature, making it more like 19C.
However, the Met Office says it is still well above average for this time of year but added that the warm weather will not stick around for long as the tail end of Hurricane Humberto blows towards the UK from the Bahamas, bringing wind and rain from Monday - the first day of autumn.
Ms Smith said: “On Sunday, the temperature will start to turn downwards - we could still see a high of 24C (75.2F) but that will be quite isolated in the east of England.”
“From there on in, we do get unsettled weather day by day with temperatures falling down to where they should be for this time of year.“Hurricane Humberto is moving towards us and becoming very quickly downgraded so it’s not going to be a hurricane by the time it gets to us, but it will bring with it wet and windy weather. On Tuesday there will be widespread showers - the heaviest showers will be in the South West with a few rumbles of thunder.”