Later this month, portions of the United Kingdom are expected to experience temperatures soaring up to 20 degrees Celsius due to a surge of warm air detected on weather charts. WXCharts’ data suggests that temperatures will begin to climb from noon on Saturday, September 20, signaling the onset of autumn across many regions after a notably hot summer. Despite the recent cooler weather with heavy rainfall and storms in September, a shift is expected, bringing a final taste of summer to southern and central England as warm air moves in from northwestern Europe.
Cities such as Cambridge, London, and Norwich are projected to reach highs of 20 degrees Celsius, extending into the evening before gradually dropping to the high teens on September 21 and stabilizing around the average monthly temperature of 17 degrees Celsius in the following days.
Reflecting on the previous month, the Met Office confirmed that 2025 marked the hottest summer on record in the UK, with an average national temperature of 16.01 degrees Celsius taking into account both daytime highs and overnight lows. The peak temperature of the summer was recorded in Faversham, Kent, on July 1, hitting a scorching 35.8 degrees Celsius.
Looking ahead, meteorologists anticipate more unsettled weather conditions for September. Deputy chief meteorologist Tom Crabtree highlighted the development of a deepening low-pressure system over the North Atlantic, potentially bringing impactful weather to the UK, particularly on Sunday and Monday, with heavy rain and strong winds likely in the northern regions.
According to the BBC Weather outlook for the upcoming week, the weekend will be warm but breezy, with showery rain expected as a frontal system moves from west to east on Sunday. The following week will see further unsettled weather, with a mix of sunshine, sharp showers, and more widespread rain, including heavy and thundery downpours accompanied by blustery winds. The latter part of the week is expected to bring continued wet conditions, occasional heavy showers, thunderstorms, and hail, with fluctuating temperatures remaining above the September average and no significant cooling trend anticipated. Dry spells are unlikely to persist towards the end of the week.
