It comes as Wales provisionally recorded its hottest May day ever, with 32.9C measured at Cardiff’s Bute Park during a late-spring heatwave that has shattered temperature records across the country.
The figure stands more than 15C above the late-May average for the region, according to the Met Office.
The previous May record in Wales had been broken just 24 hours earlier, underscoring the rarity and intensity of the current spell of hot weather.
It follows consecutive record-setting days across the UK, with Kew Gardens in London reaching 34.8C on Monday, surpassing the long-standing national May and spring record of 32.8C last set in 1944.
On Tuesday, Kew Gardens recorded 35.1C, while Heathrow reached 35.0C – marking the second day in a row that the UK’s May temperature record was provisionally broken.
The Met Office identified Kew Gardens, Heathrow, and locations across London, the Midlands, and East Anglia as the hottest areas, each recording temperatures above 33C.
Met Office chief forecaster Andy Page said: “This is exceptional late-spring heat.”
Highs of 32–33C are likely in parts of south-west England as the peak shifts west.
London is forecast to reach 32C on Thursday and 30C on Friday, before conditions begin to ease over the weekend.
Wales will continue to experience several more days of warm, humid weather before temperatures drop towards seasonal norms.
The UK Health Security Agency (UKHSA) has issued Amber and Yellow heat health alerts, citing risks to older adults and those with pre-existing health issues.
Kenley Airfield in south London recorded a minimum overnight temperature of 21.3C, a new UK record for the highest daily May minimum.
Met Office scientists say climate change is increasing the likelihood of such late-spring heat events.
A recent climate attribution study published in the Royal Meteorological Society’s journal Weather concluded that breaking the previous UK May record of 32.8C is now approximately three times more likely in today’s greenhouse gas-warmed climate compared to a climate without human influence.
The HadUK-Grid dataset reveals a clear upward trend in UK May mean temperatures since the late 19th century, despite some year-to-year variability.
Full data for May 2026 will not be available until early June.
This week’s record-breaking temperatures are seen by experts as part of a broader pattern of rising temperatures and an increasing frequency of extreme heat events due to climate change.
A yellow thunderstorm warning was in effect on Tuesday evening, with forecasters predicting further risk of storms in the coming days as the heat continues across much of England and Wales.
The Met Office and UKHSA have directed the public to their WeatherReady guidance for more information on staying safe during periods of hot weather.
Advice includes staying out of the sun during the hottest part of the day, keeping living spaces cool, and checking in on those who may be more vulnerable in extreme heat.
