Forecasters say Portsmouth is likely to enjoy the hottest day of the year so far tomorrow.
But a severe weather warning has been issued for thunderstorms and hayfever sufferers have been told to expect very high pollen levels.
The Met Office forecast for tomorrow says: ‘A fine morning with some sunny spells, though heavy thundery showers will spread from the south during the afternoon, ahead of heavy rain overnight. Feeling very warm in the afternoon. Maximum temperature 27°C.’
The conditions are set to be caused by warm, humid air from France arriving in the south tonight.