Full Breakdown
September Heatwave Forecast for the United Kingdom
By Drooid · · How we work
Forecast Overview
Weather forecasting services have released maps for the period from September 19 through September 28 that indicate a sustained spell of hot weather across much of England. The models show a “volcanic red” band of high temperatures beginning on Thursday and intensifying through the weekend, with a final surge expected from September 24 onward before cooler conditions return.
Expected Temperatures by Region
- South West: peaks at 27 °C on Thursday.
- London and the South East: rise to 26 °C on Thursday, climbing to 27 °C on Friday.
- Midlands: the West and East Midlands are forecast to reach 27 °C on Friday.
- South London, Surrey, Cambridgeshire, Berkshire, Wiltshire, and Somerset: projected to hit 29 °C, the highest values in the spell.
- Yorkshire/Humber and other northern areas: expected to remain cooler, generally below 25 °C.
The heat is set to persist into Sunday, with the majority of southern England experiencing highs near 29 °C.
Met Office Heatwave Definition
According to the Met Office, a heatwave is defined as an extended period of hot weather where the daily maximum temperature meets or exceeds a specific local threshold for at least three consecutive days. For southern England at this time of year, the threshold lies between 26 °C and 28 °C. The forecasted temperatures therefore satisfy the criteria for a heatwave across much of the south.
Potential Impacts
The prolonged warmth may bring dry, settled conditions to the south, as noted in the forecast narrative for the September 19-28 window. Such weather can increase demand for cooling, affect outdoor activities, and raise the risk of heat-related health concerns, especially for vulnerable populations. Residents in the most affected counties are advised to stay hydrated and monitor local advisories.
Outlook After the Heat Spell
The models indicate that the heat will subside after the September 24 peak, with cooler temperatures returning later in the month. No further extreme heat is projected beyond the September 28 date.