The UK experienced a North-South divide in its weather today, with Londoners set to swelter through the hottest day of the year while Britons elsewhere suffered thunderstorms.
The current sunny spell is the hottest since July 2006, with yesterday seeing the highest temperatures of the year at 31.8C (89.2F).
But although the mercury is set to soar still further in the South East, the North and West have been hit by downpours.
Tiffany Curnick, a forecaster for MeteoGroup UK, the weather arm of the Press Association, expected temperatures to reach around 32C (89.6F) in the London area.
"We've got the hottest day of the year in the East but further north and in the West it's really unsettled and thundery," she said.
"There is a band of thundery rain across south-west England, the West and Northern Ireland and this morning there will be a lot of thunderstorms in Scotland as well."
The Met Office likewise predicted that today would be the peak of the heatwave in the capital, with temperatures generally "a degree or two up on on Wednesday".
Players at Wimbledon faced hot and sunny weather although there was a small risk of a light shower in the evening, before the weather turns more unsettled tomorrow.
Meanwhile, fears over flooding have eased since the Environment Agency warned yesterday that the heavy rain could lead to flash floods.
A spokesman said: "There was some very localised flash flooding, mainly in agricultural areas, last night in the North East and we've heard some reports of some flash flooding in Durham.
"However the worst of that seems to have passed now.
"We are watching the South West but rivers there so far are not responding (to the rain) and the ground is still taking on water. There have been no reports to us of any flash flooding.
"We continue to monitor the situation."
Forecasters have already raised the heatwave warning alert level from two to three.
The heatwave plan alert is in four stages, with green level one signalling "summer preparedness and long-term planning".
Level two is amber and signals "alert and readiness", while three is red for "heatwave action". Level four is classed as "red emergency".
Wayne Elliott, head of health forecasting at the Met Office, said: "There are four key things to try and remember during a heatwave.
"If possible, stay out of the heat during the middle part of the day, cool yourself down, keep your environment cool and look out for others, especially older people, those living alone, babies and young children."
The London Ambulance Service said it had seen a busy few days and urged people to only call for an ambulance in a genuine emergency.
Crews have been treating large numbers of patients for breathing problems, chest pains, loss of consciousness and fainting.
It has also emerged that a 17-year-old boy died while swimming with friends in a reservoir near Hebden Bridge, West Yorkshire, yesterday afternoon.
And there was a grim reminder that animals can be vulnerable to the heat, after two German shepherd police dogs died when their handler left them in a car outside Nottinghamshire's force headquarters in Arnold.
As people attempted to cope with the heat, department store chain Debenhams said demand for children's sunhats has soared, with enough sold in June to shade every child who visited Legoland on the May Bank Holiday weekend.
Figures also suggested that men are ditching suits and shirts for more casual clothes to stay cool in the office, with sales of casual shorts up 204% week on week.
Demand for the store's light three-tog duvets has likewise undergone a dramatic increase, with average weekly sales more than doubling in June compared with the previous month.
Sales of self-tanning products also rose, up 16% week on week, suggesting consumers are more aware about the long-term effects of sun damage.