Is a September heatwave forecast for the UK?

Is a September heatwave forecast for the UK? By Ben Rich, Lead Weather Presenter Temperatures are expected to rise across the UK this weekend, reaching summer‑like levels in some areas. The air will feel warm and muggy, especially during sunny spells, although periods of heavy rain are also part of the forecast. The warmth should linger into Monday in many regions, but no location is forecast to meet heatwave criteria, with cooler conditions anticipated by midweek. Computer models show a mixed outlook for the second half of September. While occasional warm spells are possible, there are currently no clear signs of an impending heatwave. How warm will it get this weekend? Rain outbreaks will move southward on Saturday, clearing from Scotland and Northern Ireland but persisting through the day across parts of England, Wales and the Midlands. Some of the rain could be intense, with a chance of thunder and lightning, and will be accompanied by brisk south‑westerly winds. Southern England should remain largely dry with sunny intervals, feeling particularly warm and humid as temperatures climb into the mid‑20s Celsius—several degrees above the September average. Two weather maps for the UK this weekend depict Saturday daytime and Sunday afternoon conditions. On Saturday, temperatures range from 14 °C in Lerwick to 23 °C in Norwich and London. On Sunday, they range from 13 °C in Lerwick to 24 °C in London. The caption notes that typical mid‑September temperatures run from 14 °C in blue‑tinged Scotland to 19 °C in south‑east England. On Sunday, rain may linger for a while in southern England before giving way to a dry day for much of the UK, with sunny spells and light winds. Temperatures may dip slightly in the northern half of the country but rise a little further south. Parts of Wales, the Midlands and southern England could reach 23‑25 °C. Monday could be even warmer, with highs of 22‑26 °C across much of England and Wales and around 20 °C likely in parts of Scotland and Northern Ireland. Despite the warmth, readings will stay below the thresholds that define a heatwave. Meeting heatwave criteria would require three consecutive days of temperatures above a variable threshold—25 °C for Scotland and Northern Ireland and 28 °C for the London area. Is there hot weather in the long‑range forecast? Current model output suggests unsettled conditions will continue through the coming week or so. The jet stream is expected to steer areas of low pressure across the UK, bringing spells of rain and possibly gusty winds. The prospect of wet weather would be welcome for the extensive drought‑affected regions of England and Wales. Later in the month, zones of high pressure may gain influence, potentially leading to longer dry intervals and a greater chance of above‑average daytime temperatures. Although long‑range forecasts carry uncertainty and details can shift, there is presently nothing to indicate a heatwave is on the cards. As autumn advances and nights lengthen, any lingering high pressure could instead produce chilly mornings. Members of the public can monitor local temperatures via the BBC Weather website and its mobile app.