The Met Office has issued the Heat Health Watch Level 3 for South-East England.
Threshold temperatures for heatwave in South-East England are 31degC during the day or 16degC overnight.
The Met office says that there is a 90 per cent probability of heatwave conditions between today (Monday August 6) and 9am on Wednesday (August 8).
Today looks set to be a fine, dry and hot day with plenty of blue sky and sunshine.
There will be very little if any cloud around and there will be light winds.
Tonight is going to remain dry with predominantly clear, starry skies and few if any clouds.
Winds will remain light, perhaps allowing the odd mist patch to develop. Quite a warm night.
Tomorrow (Tuesday August 7) will remain largely dry with sunny periods and it will become hot again.
There will be somewhat more cloud during the afternoon with the threat of some heavy, thundery showers during the evening.
The Met Office says the impact of the hot weather will be on the very young, the elderly and the seriously ill.
In particular, very hot weather can make heart and breathing problems worse.