Just when Brits were preparing to pack away their summer wardrobes, the weather is pulling a massive U-turn. A sudden surge of late-summer warmth is set to sweep across the UK next week, sending temperatures soaring up to a peak of 26°C.
While much of northern Europe is settling into autumn, a shift in atmospheric pressure is bringing one last blast of sunshine. However, this unexpected warm spell comes with a serious warning for the country's water supply.
Why It's Getting Warm Again
The sudden shift in weather is all down to the jet stream. After a week of blustery Atlantic winds and rain, the high-altitude jet stream is buckling to the north of the UK. This movement allows a high-pressure system to build across the country, dragging in warm, humid air from the mid-Atlantic.
While the weekend will start cloudy and damp in southern England and Wales, conditions will clear up by Sunday afternoon. By Tuesday, the mercury is expected to climb:
- South-East England: Peaking at 25°C to 26°C.
- The Rest of the UK: Reaching the low 20s across Wales, Northern Ireland, and Eastern Scotland.
This is significantly higher than the typical late-September seasonal average of 15°C to 21°C.
A Record-Breaking Year
If you feel like this year has been unusually warm, you are correct. The upcoming mini-heatwave will add to what has already been a historic year.
The year 2026 has officially broken the record for the most days exceeding 25°C in the UK. The previous record of 89 days, which had stood since 1959, was surpassed just last week. Next week's high temperatures will push that record even further.
The Worrying Catch
While sunseekers will welcome the return of T-shirt weather, environmental scientists and water companies are deeply concerned. The high-pressure system bringing the sunshine also means virtually no rain for areas already suffering from severe drought.
Recent rainfall has done very little to replenish depleted reservoirs. For context:
- Leconfield, East Yorkshire: Received just 11% of its average September rainfall by mid-month.
- Durham: Received only 14% of its typical monthly average.
Experts warn that the UK needs at least seven months of relentless, steady rain to fully recover from the ongoing drought. A week of dry, 26°C heat will only push water systems further to the brink.
