A weather expert has warned that London could experience 40C heatwaves this summer, with temperatures potentially spiking above 30C. Jim Dales of the British Weather Services described the 40C threshold as an 'outside bet' but emphasized that notable heat spikes are expected.
Global Warming and Fossil Fuels
Dales attributed the forecast to record-high fossil fuel emissions, stating, 'There's no getting away from the fact that fossil fuel emissions are at a record high and therefore nothing is changing as far as the air temperatures [are concerned]. I would expect that at intervals we will see notable spikes in heat.'
El Niño's Role
Another factor is El Niño, a complex weather pattern from ocean temperature variations in the Equatorial Pacific. Dales explained that while London is not directly affected, the knock-on effect from regions like West Africa, North Africa, Spain, and the Mediterranean can bring a southerly airstream, pushing up temperatures globally.
'El Niños have a real capacity of pushing up temperatures right across the globe, never mind where they normally are, but including ourselves,' he added.
Historical Context
Both spring and summer 2025 were the UK's warmest on record, according to Met Office data. Persistent high-pressure systems brought prolonged sunshine and four heatwaves from mid-June to mid-August. Spring was also the driest in over 100 years, leading to dry soils and wildfires.
Londoners are advised to prepare for potential extreme heat, with the possibility of temperatures reaching 40C this summer.
