The Met Office has issued its verdict on the heatwave expected in London this weekend, but an expert warns the weather will be different from the wall-to-wall sunshine seen in May. Temperatures could reach 30C on Friday (June 19) and for three consecutive days from Sunday (June 21), meeting the official heatwave threshold.
Yellow Heat-Health Alert in Place
A Yellow Heat-Health Alert has been issued by the UK Health Security Agency (UKHSA) for London and the south east of England, effective from Wednesday (June 17) until Monday (June 22). This alert indicates potential health impacts for vulnerable individuals.
Thunderstorms Possible
Despite the warmth, the Met Office warns there is a slight chance of thunderstorms across south eastern England. Deputy Chief Forecaster Gregory Wolverson said: “This week’s weather reflects a contrast we often see in summer, with more unsettled conditions passing to the north west of the UK while heat builds in the south and east. As we move towards the weekend, conditions will become more widely settled and temperatures rise. Many parts of southern and eastern England are likely to see temperatures high enough to meet heatwave thresholds. It’s important to note that while temperatures may be high, we might not all see the wall-to-wall sunshine and blue skies we experienced back in May because there is more cloud around. There is also a chance of thunderstorms developing in places, particularly later each day, which could bring heavy showers and localised impacts.”
Temperature Forecast
A Met Office spokesperson said: “Temperatures are expected to climb steadily, with southern parts of England approaching 30C by Friday, depending on cloud cover, and becoming very warm more widely through the weekend. Some areas in the south and south east of England are likely to see heatwave criteria met by Saturday and more widely on Sunday, with the potential for temperatures to reach the low 30s in the warmest locations.” Headline maximum temperatures are 32C on Friday in East Anglia, 28C on Saturday, 32C in the south and southeast on Sunday, and a potential 33C on Monday in the same areas.
In May, a record high of 35.1C was recorded at Kew Gardens on May 26, with temperatures topping 30C for six consecutive days in some areas.
London Weather Forecast in Full
According to the Met Office, the London forecast for the next week is:
- Wednesday, June 17: 25C, sunny intervals, humidity 78%
- Thursday, June 18: 27C, sunny intervals, humidity 86%
- Friday, June 19: 30C, sunshine, humidity 84%
- Saturday, June 20: 27C, sunny intervals, humidity 84%
- Sunday, June 21: 30C, sunshine, humidity 72%
- Monday, June 22: 30C, sunshine, humidity 78%
- Tuesday, June 23: 30C, sunshine, humidity 76%
Heatwave Rules for London
In the UK, a heatwave is officially declared when a location records at least three consecutive days with temperatures meeting or exceeding a threshold, which varies by county. In London, the threshold is 28C for three days.
