Thursday was the hottest day of the year so far, with the mercury hitting 26.6C (79.8F) in London – and Friday is set to be even warmer across the country at up to 28C (82F).
The hot spell could persuade even more people to take to the roads for a last-minute trip, with the RAC suggesting the spring bank holiday traffic could be the busiest in four years.
But forecasters say things will start to get cooler by Saturday, especially in the east, with thundery showers moving northeastwards throughout the day.
Northern England, Scotland and Ireland could have heavy thundery showers with a risk of flooding.
Sunday will be a mainly dry and warm day but not as hot as the last few days. There could be showers in the far south and temperatures will hover at around 24C (75F).
By Monday, the temperatures are expect to dip even further to around 21C (70F) and England and Wales face heavy showers.