The UK has recorded its hottest day of the year so far with the mercury hitting 27.5C at Heathrow on Tuesday, according to the Met Office.
London sweltered in the heat, with temperatures beating the previous high for the year so far, which was 23.6C in Faversham, Kent on May 6.
Forecasters at the Met Office had predicted the weather will be "dry and very warm [with] sunny spells" across central and eastern parts of the UK.
But, they said, the hot weather will give way to clouds and heavy rain in the west later in the evening, spreading into central areas of the UK.
The Met Office’s Richard Miles said the warm temperatures were “largely confined to the south-east of England”.
But he added that the weather is expected to "generally be cooling" from Wednesday until the weekend, when temperatures will be "about the average for the time of year".
Mr Miles said: “Obviously the warmest temperatures of the year so far, it is largely confined to the south-east of England; other areas will be generally fine but not quite as warm.
“There is a risk, certainly today, of quite a bit of rain around. Tomorrow, drier, although there will be some convective showers.”
He added: “The main reason for the warmth will be the higher pressure of the continent which is where the plume of warmer air will reach into the south of the UK, so it is basically a warm air flow from the continent to the south, but it is being pushed further eastwards then maybe it looked last week.”
Mr Miles said the balmy temperatures in the south-east will be met with the “westerly systems bringing the more unpredictable and showery weather”.
He added: “The story of the week will really be low pressure systems in the Atlantic will be pushing up weather fronts in the western side of the country.
“Pushing and bringing up frontal rain and, in the south and the east of the country, where the warm air from the continent is causing some convection, that will produce showers in those areas.
“There are two different ways weather is delivered but everyone will get some, but tomorrow will be largely nice and the warmest day of the week.”
He predicted the weather will “generally be cooling” from Wednesday until the weekend, when temperatures will be “about the average for the time of year”.
