Parts of the UK are forecast to bask in 27C (81F) heat on Tuesday – but there is a risk of flooding as thunderstorms sweep in first.
The Met Office has issued a yellow weather warning for thunderstorms covering most of southern England and parts of South Wales including Cardiff.
It began at 8pm on Sunday and continues until 5am on Monday.
There is a “small chance that homes and businesses could be flooded quickly”, the Met Office said.
There may also be “lightning strikes or hail”.
Once that period has passed, conditions are looking a lot more promising.
The top temperature in the east of England on Monday is forecast to be 23C (73F), with 19C (66F) in Belfast and 20C (68F) in the northwest of England and North Wales.
Then things really hot up on Tuesday with highs of 27C (81F) forecast for East Anglia, 24C (75F) for the southwest of England, and 18C (64F) for northern Scotland.
Sky News forecaster Jo Wheeler said Monday will be a warm day in the south but there will be a “muggy feel to the day”.
On Tuesday, “eastern parts of the country should have a lovely day with sunshine and a high of 27C”, she added.
After that temperatures will drop a few degrees, with eastern England forecast to be back down to 23C on Thursday.