Temperatures have soared this summer (Image: Getty)
UK weather maps are lighting up with the tell-tale signature of an Iberian plume, as hot air drawn north from Spain and Portugal edges north. The latest GFS runs show temperatures climbing into the high 20s across southern and eastern England this weekend, with the potential for isolated spots to flirt with the 30C mark if the sun breaks through fully. Met Office forecasts put the peak around 26-28C in the south-east on Sunday, delivering a final taste of summer after the record-breaking heat of 2026.
14 areas are firmly in the frame for the highest readings with them covering large parts of Greater London, Berkshire, Oxfordshire, Cambridgeshire, Northamptonshire, Warwickshire, Gloucestershire, Worcestershire and surrounding counties. Inland spots away from any sea breeze stand the best chance of the top values.
WX Charts’ map for September 19 (Image: WX Charts)
An Iberian (or Spanish) plume forms when very warm air is pulled northwards from the Iberian Peninsula on a southerly flow. Combined with strong sunshine heating the surface and cooler air aloft, it can produce sharp temperature rises – and sometimes thundery breakdowns.
This time the setup is milder than the extreme heatwaves earlier in the summer, but still enough to push values well above the early-September average. Charts for the middle of the month continue to flag warmer-than-normal anomalies across the south and east, with continental Europe remaining firmly in the red.
Sunday looks the standout day. After a bright and breezy Saturday, cloud and some rain will affect northern and western areas, but the south and southeast should see plenty of sunshine once any early rain clears. London, the Home Counties, East Anglia and parts of the Midlands are in the firing line for the highest readings.
Coastal spots will feel a touch cooler under any sea breeze, while inland valleys could edge higher. Further north and west the warmth is more muted, with highs closer to the low 20s and a greater chance of showers.
The Met Office currently has no heat warnings in force – a contrast to the amber and red alerts that dominated parts of the summer. Instead, yellow warnings for rain and wind are more likely later next week as Atlantic systems return.
That unsettled pattern will bring the brief warm spell to a fairly sharp end, with temperatures dropping back towards seasonal norms and stronger winds possible.
The redder the map, the hotter the weather (Image: WX Charts) Get top stories from The Express sent straight to your phone Join us on WhatsApp
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Still, the late burst will be welcomed by many after a summer that has already rewritten the record books. Provisional figures show 2026 as the UK’s hottest on record, and any extra warmth in early autumn will add to the sense of a season that refuses to quit. Gardens, parks and beer gardens in the warmer counties should see a surge in activity while the sun lasts.
Practical advice remains straightforward: stay hydrated, seek shade in the middle of the day if you are sensitive to heat, and check the latest forecasts before planning outdoor events.
The plume is not expected to lock in for days, so the window is short. By the middle of next week the jet stream looks set to reassert itself, ushering in more typical September fare of sunshine and showers, with the focus shifting north and west for the wettest conditions.
The WXCharts maps point to a short-lived Iberian surge is delivering a final 20s scorcher to the South-east before autumn weather reclaims the stage.
The 14 hottest areas:LondonReadingBristolOxfordSt AlbansCambridgeNorthamptonStratford-upon-AvonCoventryHuntingdonGloucesterWorcesterElyPeterborough