Suffolk and Essex could record the hottest day so far this year today - with temperatures set to soar to 29C (84F) ahead of late-night thunderstorms.
Families were making the most of the heat, as forecasters warn thunderstorms are set to arrive late tonight, meaning the end of the current spell of sunshine.
Forecaster Adam Dury said: "This will be one of the hottest days of the year. We have had temperatures of 27-28C, and today it looks likely to be 28C and possibly 29C in Essex."
He added it would be a sticky night and people could have problems sleeping, as temperatures are unlikely to fall below 17-18C.
The Met Office has issued a yellow weather warning for Suffolk running from late tonight through to Friday, with thunderstorms and possible flooding predicted.
Mr Dury said the storms were expected to arrive around midnight and rain is likely to continue until between 9 and 10am tomorrow.
The rest of Thursday is likely to be dry, with top temperatures of 22C, but there will be more rain on Friday.
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