UK Weather: Temperatures Could Reach 29C in September, Met Office Says Heatwave Unlikely

Forecast Points to Late-Summer Warmth

Weather maps from WXCharts, using Met Desk data, suggest that temperatures could climb to nearly 30C in parts of the UK on Tuesday, 15 September, according to reports from the Derby Telegraph and Leicester Mercury. By midday, southern regions are expected to see temperatures around 27C, with London forecast to be the warmest spot. Hertfordshire, Bedfordshire, and coastal areas including Brighton are also predicted to reach 27C.

Later in the day, by 6pm, temperatures are expected to climb further. London, Berkshire, Surrey, and parts of West Sussex could reach 29C, the maps indicate. Areas stretching towards Northamptonshire are expected to reach 27C, while Oxfordshire may see 26C and much of the Midlands around 25C. Further north, Manchester and its surroundings are likely to stay cooler at about 20C, with Greater Manchester and parts of Yorkshire possibly rising to 23C by evening.

The Met Office has suggested that September could bring further "very warm spells," particularly across the south of England. Its long-range forecast for September 6–15 states that temperatures are likely to be near average, though brief warm or very warm spells are possible, especially in the south.

Summer's Record Heat

The Met Office confirmed that this year's summer was the hottest on record for the UK. The season recorded a provisional average mean temperature of 16.5C, and it was the warmest in records dating back to 1884. The forecaster also noted a slight dip in temperatures towards the end of August, but the upcoming warm spell is anticipated to follow.

Heatwave Criteria and Likelihood

The Met Office officially declares a heatwave when temperatures hit the "heatwave threshold" for three consecutive days. In the south-east, where conditions are typically warmer, the threshold is 28C. Temperatures on 15 September are forecast to meet these criteria, according to the weather maps.

However, the Met Office suggests that an official heatwave declaration currently appears unlikely because the warm spell is not anticipated to persist beyond the brief period. The long-range forecast for September 6–15 indicates that "an unsettled period is likely, with many places seeing showers or longer spells of rain at times." Rain is expected to be most frequent across northern and western areas, while the south and east are more likely to see drier interludes. The forecast also notes potential for strong and gusty winds, particularly in the northwest.

While the immediate outlook points to a brief warm respite in the south, the broader forecast suggests that the late-summer warmth may not last long, as conditions are likely to turn more unsettled.