Temperatures are set to climb across the UK this weekend, with the UK September warm spell 28°C Met Office forecast pointing to warm, muggy weather and no area reaching heatwave criteria. Southern England could see the highest values on Saturday, with mid-20s Celsius possible, but the pattern still falls short of a heatwave.
The Met Office says a heatwave needs three consecutive days above a regional threshold, ranging from 25C in Scotland and Northern Ireland to 28C in the London area. The forecast puts much of England and Wales in the 22-26C range on Monday, while parts of Wales, the Midlands and southern England could reach 23-25C on Sunday.
Saturday rain and southern sunshine
Outbreaks of rain will spread southwards during Saturday. Rain will clear from Scotland and Northern Ireland, then continue into the afternoon across parts of northern England, Wales and the Midlands. Some of the rain could be heavy, with thunder and lightning, and it will be accompanied by brisk south-westerly winds.
Southern parts of England should stay largely dry with sunny intervals, and temperatures there could climb into the mid-20s Celsius. That creates the contrast in this forecast: summerlike warmth in some places, but heavy rain in others, with no area lining up three hot days in a row.
Sunday and Monday across UK
On Sunday, rain may linger for a while in southern England before much of the UK turns dry in the afternoon with sunny spells and light winds. Parts of Wales, the Midlands and southern England could reach 23-25C, which is warm for mid-September, when typical temperatures range from 14C in northern Scotland to 19C in south-east England.
On Monday, highs of 22-26C are forecast across much of England and Wales, with 20C likely in parts of Scotland and Northern Ireland. The warmth is set to persist into Monday in many areas, but it still does not build into the three-day run needed for heatwave conditions.
Later in September weather
Computer models suggest unsettled weather will continue over the next week or so, with the jet stream bringing areas of low pressure across the UK. That would mean more spells of rain and some blustery winds, while wetter conditions will be welcome for large swathes of England and Wales that remain in drought.
Later in the month, areas of high pressure may take more of a role, bringing longer dry interludes and a chance of above-average daytime temperatures. For now, though, there is nothing to point to a heatwave, and cooler conditions are due to return by midweek.
