Heavy rain and thunderstorms hit London before 30°C heatwave

Key points

• Heavy rain and thunderstorms drench London at the start of the week
• Temperatures set to rise with highs of 31°C expected by Thursday
• Heatwave could be declared by Friday if warm conditions persist
• Night-time temperatures to remain high, increasing discomfort
• UV and pollen levels forecast to be very high across the south

Thunderstorms soak London before summer heat returns

Londoners faced a wet and stormy start to the week as heavy rain and overnight thunderstorms swept through the capital. Monday morning saw widespread downpours, leaving commuters reaching for umbrellas and Wimbledon ticket hopefuls queuing in ponchos.

The unsettled conditions followed a burst of thunderstorms on Sunday afternoon and continued into the early hours of Monday, prompting caution across the city. The Met Office has not issued a formal weather warning for thunderstorms, but conditions remain unstable.

Temperatures expected to climb through the week

According to the Met Office, Monday will gradually clear, with sunny intervals forecast later in the day. Temperatures are expected to peak at around 23°C, before rising steadily through the week.

By Wednesday, temperatures could reach between 25°C and 28°C in parts of the country. However, for a heatwave to be officially declared, these thresholds must be met for three consecutive days.

Senior Met Office meteorologist Marco Petagna explained: “Although the temperature will be reaching the criteria, we probably won’t actually reach an official heatwave until around Friday.”

Heatwave likely by Friday, with weekend highs in low 30s

The mercury is forecast to hit 30°C or above by Friday and Saturday, with some areas potentially reaching the low 30s. Conditions are also expected to become more humid towards the weekend, making nights increasingly uncomfortable as temperatures are not likely to fall below 15°C.

Petagna noted that while it will be hot, the UK is expected to avoid the extreme heat experienced in southern Europe, where parts of Spain and Portugal have seen temperatures soar into the mid-40s.

UV and pollen levels also rising

In addition to the heat, very high UV and pollen levels are expected across southern parts of the UK later in the week. The Met Office has advised the public to take precautions during peak hours of sunlight.

The long-term outlook remains uncertain, with some forecasts suggesting the heat may ease early next week, while others predict it could persist into the following weekend.