UK Weather 34c Heat Surge Maps Emerge But Met Office Cools September Heatwave Signal

Weather maps have raised the prospect of temperatures climbing to 34C again, but the latest Met Office forecast is considerably more cautious, with London expected to stay in the low-to-mid 20s over the coming week.

Reports of a UK weather 34C heat surge have emerged as forecasting models indicate another sharp rise in temperatures could develop but the Met Office’s newest official outlook does not currently confirm a return to widespread extreme heat.

The Daily Star and Mirror reported on Thursday, 20 August that weather-model maps showed temperatures potentially reaching 34C, with 15 areas or counties forecast to reach at least 31C. Both reports linked the projections to the possibility of further hot weather after an exceptionally warm summer.

However, the latest Met Office long-range forecast, updated on Wednesday, 19 August, points to a more mixed picture through the end of August and beginning of September.

For the period from 24 August to 2 September, the forecaster expects temperatures to remain close to average overall, although short-lived warm and humid spells remain possible, particularly across southern Britain. Low pressure is expected to become more influential during the period, bringing showers or longer periods of rain to many areas.

London Forecast Shows No Immediate Return to 34c

For London, the short-range forecast currently gives little indication of another major heatwave in the coming days.

The Met Office forecast published early on 20 August puts the capital at around 22C on Thursday, followed by 21C on Friday and Saturday. Temperatures are then expected to reach about 23C on Sunday and Monday before climbing to approximately 25C on Tuesday and Wednesday.

That would leave London well below its official heatwave threshold. A heatwave is recorded when a location reaches or exceeds its regional temperature threshold for at least three consecutive days. Across Greater London and the Home Counties, that threshold is 28C.

The Met Office’s London and South East regional forecast also expects conditions to become more settled towards the weekend after thundery showers on Thursday, but says temperatures will be below average for August.

The distinction is important because individual weather-model runs can show specific temperatures well beyond the period covered by higher-confidence short-range forecasts.

Those projections can change substantially as the date approaches and should not be treated as confirmed Met Office maximum temperatures.

September Heat Remains Possible, but Outlook Has Changed

Earlier long-range forecasts had raised the prospect of late-season heatwaves, particularly in southern Britain. That possibility prompted separate reports that London could experience a sixth heatwave of 2026.

The newer Met Office forecast is less bullish.

For 3 to 17 September, it says a relatively unsettled opening to meteorological autumn is most likely, with showers or longer spells of rain alternating with drier periods. Temperatures are expected to fluctuate around average.

The forecast still allows for some warmer conditions, saying

“some warm or hot spells are possible but unlikely prolonged in early September”.

Signals become weaker further into the period, although more settled conditions could become increasingly likely across southern and eastern England by mid-September.

Any renewed heat would follow an extraordinary summer for London. Temperatures provisionally reached 38.1C at Kew Gardens during last week’s heatwave, a reading the Met Office said made it the fifth-hottest day recorded in the UK.

For now, therefore, the 34C figure remains a longer-range model possibility rather than a confirmed Met Office forecast for London. The official outlook supports the possibility of occasional warm or hot spells, but its latest update no longer points towards a prolonged early-September heatwave.