The Met Office says temperatures could reach the mid-30s in the South East on Monday but yellow thunderstorm warnings are set to come into force for northern England, Scotland and Northern Ireland.
Severe weather warnings for thunderstorms have been issued for large parts of the UK after temperatures soared this weekend.
Yellow warnings are in place for northern England, Scotland and Northern Ireland on Monday, with forecasters warning the storms may cause disruption and damage to buildings.
The warning for northern England and Scotland is in place from 2am on Monday until 1pm that day, while the alert for Northern Ireland begins after midnight until 7am.
It comes as much of the UK enjoys hot weather this weekend, with temperatures expected to reach as high as 33C.
The hot spell is partly due to Storm Debby, which battered parts of the south of the US earlier this week.
The tropical weather works to strengthen the jet stream – a core of strong winds in the atmosphere which has a significant influence on UK weather – causing it to meander in the Atlantic.
That, weather experts say, is causing hot air to rush into the UK this weekend and early next week.
By Tuesday and Wednesday, temperatures are expected to return to average.
The rise in temperature is not considered a heatwave, the Met Office said, as temperatures need to exceed a specific threshold over three consecutive days in order to meet the criteria.
