Heat Wave: The UK’s warm weekend and Monday will stay below heatwave criteria
The UK is expected to turn warm and muggy this weekend, but a heat wave is not currently forecast. Temperatures may reach the mid-20s Celsius in parts of England and Wales before cooler conditions return by midweek, according to the latest available reporting.
The UK’s warm weekend and Monday will stay below heatwave criteria
Rain is expected to move southwards on Saturday, with some heavy bursts and a chance of thunder and lightning across parts of northern England, Wales and the Midlands. Southern England should be drier, with sunny spells and temperatures in the mid-20s Celsius, several degrees above the September average. BBC Weather
Sunday is expected to be drier for much of the UK after any lingering rain clears. Temperatures could reach 23-25C in parts of Wales, the Midlands and southern England. Monday may be warmer still, with highs of 22-26C across much of England and Wales, and around 20C in parts of Scotland and Northern Ireland.
That warmth is not expected to meet the UK heatwave definition. The threshold requires temperatures to exceed a location-specific level for three consecutive days. The threshold ranges from 25C in Scotland and Northern Ireland to 28C in the London area, meaning a single warm day would not be enough to qualify.
What the forecast says about the next week
The outlook remains unsettled, with areas of low pressure expected to bring further rain and potentially blustery winds. Cooler conditions are due to return by the middle of next week, although some regional forecasts indicate that temperatures could rise again beforehand.
A report focused on the South West says forecasting models suggest temperatures could reach 28C in some parts of the UK next week. It gives possible highs of 23C in Bristol on Monday and 24C in parts of Somerset, while warning that temperatures are expected to fall again across the South West after Monday. Bristol Post
In Suffolk, temperatures of 23-24C are forecast in inland areas, with coastal towns potentially reaching 22-23C. The warmer spell may continue into Tuesday, September 22, but cloud and rain, including some heavy outbreaks, are also expected. East Anglian Daily Times
These projections point to warm spells rather than a confirmed nationwide heatwave. The BBC’s assessment says computer models show a mixed picture for the second half of September, with no definitive signs of heatwave conditions at present.
Why a later September heatwave remains uncertain
Longer-range forecasts suggest that changeable weather may continue, with rain or showers more frequent in northern and western areas and drier, more settled periods possible in the south. Later in September, high pressure could become more influential, bringing longer dry spells and the possibility of above-average daytime temperatures.
However, the same outlook also allows for relatively cool nights, and forecast details may change. The available reporting does not establish that any later warm spell will last long enough, or reach high enough temperatures across enough locations, to meet heatwave criteria.
The latest verified position is therefore a warm weekend and potentially warm Monday, followed by a return to cooler or more unsettled conditions. There is currently no confirmed UK heatwave forecast.