The Met Office has warned of the threat of thunderstorms across South Yorkshire today.
Forecasters said most parts will have a fine morning, with some sunshine.
This afternoon, the sunshine will be hazy at times and thundery showers may develop.
It will not be as hot as yesterday, when temperatures reached 32.6C in Sheffield, with a maximum temperature of 24C.
Tonight will stay warm and clear with temperatures falling no lower than 13C.