The UK has experienced the hottest day of the year so far.

Temperatures hit 28.3C (82.9F) on Monday in Wisley, Surrey, after a four-day heat health alert came into effect.

In London, the temperatures peaked at 27.4C (81.3F) in St James’s Park while Aberdeenshire saw the mercury hit 26.9C (80.4F).

There is set to be a heatwave across parts of the UK as temperatures could rise even further later in the week – getting as high as 31C (87.8F).

However, the hot weather is not expected to last for very long as a cold front is moving in from the South.

Check the weather forecast where you are

Sky News meteorologist Dr Chris England said: “We’ve had the highest temperature of the year so far, with 28.3C recorded at Wisley today, and it looks likely to turn even hotter, with 30C likely tomorrow, and 31C possible on Wednesday.

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“That looks like the last of the generally hot days in the current spell, as a cold front moving south on Thursday will bring the cooler air to most parts, but the South may well reach 31C again, with the cooler conditions not arriving there until evening.”

This comes after the UK Health Security Agency (UKHSA) and Met Office issued a joint heat health alert that lasts from 8am on Monday until 5pm on Thursday.

The public enjoys the summer sun in Green Park, London. Pic: PA
Image:
Green Park in London. Pic: PA

Some people make the most of this week's sun, entering the sea on Crosby Beach, Merseyside. Pic: PA
Image:
Crosby Beach, Merseyside. Pic: PA

The UKHSA said: “We expect the hot weather to have minor impacts across the health and social care sector for every region in England except the North East.”

There is potential for “significant impacts” which could include an “observed increase in mortality across the population, particularly in the 65+ age group or those with health conditions, but impacts may also be seen in younger age groups,” it added.

Pic: UKHSA
Image:
The yellow areas represent the more serious impact of the heat in this week’s health alert. Pic: UKHSA

Alongside that, hay fever sufferers are in for a rough few days as pollen levels remain “very high” across almost all of the UK until Thursday.

Mark Sidaway, deputy chief meteorologist at the Met Office, also warned that “it may not be the wall-to-wall sunshine and blue skies people are expecting”.

Read more:
‘Potential for significant impacts’ as health alert issued
UK had its warmest May and spring on record
June weather forecast: A game of two halves?

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He added that some areas will hit heatwave criteria but that the weather was not “particularly exceptional or extreme”.

The heatwave threshold is met when a location records at least three consecutive days with maximum temperatures exceeding a designated value, according to the Met Office.

This is 25C for most of the UK, but rises to 28C in London and its surrounding area, where temperatures are typically higher.