London is enduring a prolonged drought as the July heatwave persists, with temperatures forecast to exceed the 28C heatwave threshold for a 12th consecutive day on Thursday. High temperatures are also expected on Friday before a slight easing over the weekend. However, the respite may be brief, as meteorologists predict a fourth heatwave of the year next week, driven by high pressure drawing hot air over the UK. Medium-term forecasts show almost no rain for London, raising concerns of a hosepipe ban and further wildfires.
Heatwave Intensity and Climate Change
Alarming changes to London’s weather have been highlighted by a new Met Office report, which reveals that the number of days over 30C and nights over 18C has more than quadrupled in the most recent decade (2016-2025) compared to the 1961-1990 baseline. The annual “State of the UK Climate” report for 2025 emphasises that temperatures are spiralling at an increasingly worrying rate, with record highs recorded this year. The “urban heat island” effect means London struggles to cool down, experiencing more tropical nights where temperatures do not dip below 20C.
Drought and Fire Risk
London has basked in ten days of heatwave conditions with daily highs above 28C since July 5. This third heatwave since May has seen the thermometer reach 34C and extended a dry spell that began on June 27, now 16 days long. The hot, dry weather has fuelled two major fires in recent days, causing significant disruption. The London Fire Brigade has warned of an “extreme” risk of wildfires, with the city facing a month with no rain and the next precipitation not expected for around ten days.
Extreme Weather Becoming the New Normal
According to a Met Office report, extreme weather is becoming the “new normal.” The hottest day of the year in southern England is now typically 4.5C warmer than between 1961 and 1990, and 2025 was the warmest year on record since 1884. Homes, schools, hospitals, and transport networks are struggling to cope, exposing the UK’s lack of preparedness for climate change. Mike Kendon, Met Office climate information scientist, stated: “We are right now living in a time of historic and unprecedented change, and in terms of temperature, on annual, seasonal, monthly and daily timescales, this evidence shows the climate of the 20th Century has now gone.”
Thursday Weather Forecast
The heatwave is forecast to continue on Thursday, with the Met Office predicting a high of 29C. The day will begin with clear spells before cloud develops in the early to mid-afternoon. Temperatures are expected to peak around then and remain above at least 21C until the end of the day.
Heatwave Officially Stretches to Eleventh Day
A provisional temperature of 28.3C was recorded in London on Wednesday, marking eleven consecutive days of heatwave conditions. The Met Office forecasts similar temperatures on Thursday and Friday, with highs in the mid-20s over the weekend.
Travel Disruptions
South Western Railway has confirmed that some services will be affected by the hot weather. Between 11am and 5pm, trains from Portsmouth to London Waterloo via Guildford will be diverted via Cobham & Stoke D’Abernon, with passengers advised to change at Guildford for Woking. National Rail warns that services across the country may be affected, with East Midlands Railway, ScotRail, and South Western Railway issuing official advice for Thursday and Friday.
Health Alerts
The UK Health Security Agency (UKHSA) has issued yellow heat-health alerts for seven English regions between Tuesday and Friday: North West, South West, South East, East Midlands, West Midlands, East of England, and London. The North East and Yorkshire and the Humber were spared. A yellow alert advises people to “be aware” and plan ahead, with a risk score of 10 (medium impact, low likelihood). People are urged to stay hydrated, check on vulnerable friends and family, and avoid direct sun.
Mayor Issues Wildfire Warning
Sir Sadiq Khan has issued a stark warning for Londoners to create firebreaks around their homes due to an “extreme” risk of wildfires. The warning follows a major blaze in Walthamstow that swept through around 30 gardens and damaged properties. The Mayor raised the alarm as London faces around a month with no rain. The hot weather is taking a toll, with an estimated 1,000 people in London and the wider South East killed by the May and June heatwaves.
