As late September settles over the British Isles, an unusual warmth has arrived — not as a gentle farewell to summer, but as a striking reminder that the seasons themselves are shifting. Southerly winds drawing heat northward from France and Spain will push temperatures to 26C in south-east England on Tuesday, some 3 to 7 degrees above what this time of year has historically offered. The warmth is not merely a curiosity of weather but a data point in a longer story: every month of 2026 has run above average, and the year is quietly positioning itself among the warmest the UK has ever recorded.
UK braces for 26C warmth as southerly winds bring late September heat
A night that stays above 20 is a summer night, not an autumn one
Mark
So we're looking at 26 degrees in parts of the south-east on Tuesday. That sounds warm for late September, but how much warmer are we actually talking about?
Mimi
Three to seven degrees above what you'd normally expect. Late September averages around 16 to 19 degrees, so this is a genuine spike—the kind of day that feels like summer has come back for a visit.
Luke
But that's just the daytime. What's the actual mechanism here? Is this just a weather system, or is there something structural happening?
Mimi
It's a southerly wind pattern pulling hot air up from France and Spain, where they've been seeing temperatures above 30 degrees. There's a deep low-pressure system moving toward Iceland that's driving the whole thing.
Mark
And the night—you mentioned temperatures might not drop below 20 degrees in some places. That's extraordinary, isn't it?
Mimi
Completely. Normal late September nights fall to 7 to 11 degrees. A night that stays above 20 is a summer night, not an autumn one.
Luke
I notice the piece mentions September is already 2.6 degrees above normal through the 26th, and every month this year has been above average. How confident are we that 2026 ends up as one of the warmest years on record?
Mimi
The Met Office is forecasting a mild autumn and early winter, so unless something dramatic shifts in the next few months, it's looking very likely.
Mark
So this warm Tuesday isn't an anomaly—it's part of a pattern.
Mimi
Exactly. It's one warm day in what's shaping up to be a very warm year.
Luke
The winds are also notable—50 miles per hour gusts in Scotland and Northern Ireland. That's not just warm, that's windy too.
Mimi
Right. It's not a gentle warm spell. It's a vigorous system moving through.
The Pulse
- Temperatures across south-east England could hit 26C on Tuesday — readings that belong to July, not the final days of September.
- Overnight lows may refuse to fall below 20C in parts of the south-east, against a seasonal norm of 7 to 11C — a nocturnal warmth that feels more like midsummer than early autumn.
- Gusts of up to 50mph are expected in Northern Ireland and western Scotland, driven by a deep Atlantic low tracking toward Iceland and reshaping conditions rapidly across the British Isles.
- September 2026 is already running 2.6C above its historical average, with every single month this year exceeding normal temperatures — a streak that is quietly building toward a record-breaking year.
- The Met Office's outlook for October through December leans mild, offering little prospect of the sustained cold that would be needed to pull 2026 back toward historical norms.
As late September settles over the British Isles, an unusual warmth has arrived — not as a gentle farewell to summer, but as a striking reminder that the seasons themselves are shifting. Southerly winds drawing heat northward from France and Spain will push temperatures to 26C in south-east England on Tuesday, some 3 to 7 degrees above what this time of year has historically offered. The warmth is not merely a curiosity of weather but a data point in a longer story: every month of 2026 has run above average, and the year is quietly positioning itself among the warmest the UK has ever recorded.
A wave of unseasonable warmth is sweeping across the UK on Tuesday, with south-east England expected to reach 26C — a figure that sits 3 to 7 degrees above what late September typically delivers. Most of England will see temperatures in the low 20s, while Wales, Northern Ireland, and Scotland will climb into the high teens and low 20s. The morning may begin with cloud and scattered showers, but sunny spells are forecast to break through across England and Wales as the day develops.
The heat is being drawn northward by a strong southerly airflow connected to a deep area of low pressure moving across the eastern Atlantic toward Iceland. France and Spain have been enduring temperatures well above 30C, and Tuesday's winds are carrying some of that continental warmth into British airspace. Those same winds will strengthen considerably, with gusts of up to 50mph forecast for Northern Ireland and western Scotland.
Perhaps more remarkable than the daytime peak is what follows after dark. Overnight temperatures in parts of south-east England may not fall below 20C — a figure that would be notable in July, let alone at the threshold of October. Across the country more broadly, lows are expected to settle between 15 and 19C, against a seasonal norm of 7 to 11C.
This episode arrives within a broader pattern that is difficult to ignore. September 2026 is tracking 2.6C above its historical average, and not a single month this year has come in below normal. The year-to-date temperature anomaly also stands at 2.6C above average. For 2026 to avoid a place among the UK's warmest years on record, the autumn and winter would need to be markedly colder than usual — an outcome the Met Office considers unlikely, with its latest outlook pointing toward a mild close to the year.
A burst of unseasonable warmth is moving across the UK on Tuesday, with temperatures expected to climb into the mid-20s Celsius across south-east England—a sharp departure from what late September typically brings. The mercury could reach as high as 26C in the warmest spots, while most of England will see temperatures in the low 20s and Wales, Northern Ireland, and Scotland will experience highs between 17 and 22C. This represents a swing of 3 to 7 degrees above the seasonal norm, which hovers around 16 to 19C for this time of year.
The source of this warmth is a strong southerly airflow developing across the country, pulling hot air northward from continental Europe. France and Spain have been baking in temperatures well above 30C, and the southerly winds will carry some of that heat into British airspace. Tuesday morning may start cloudy with scattered showers, but sunny spells are forecast to break through across England and Wales as the day progresses. In Scotland and Northern Ireland, cloud cover will thicken as the day wears on, though temperatures will still climb well above average.
The winds driving this warmth will strengthen considerably, with gusts reaching 50 miles per hour expected in Northern Ireland and western Scotland. This vigorous southerly flow is connected to a large, deep area of low pressure moving north across the eastern Atlantic toward Iceland—the kind of system that can dramatically reshape weather patterns across the British Isles in a matter of hours.
What may prove even more striking than Tuesday's daytime warmth is the night that follows. Minimum temperatures are expected to remain unusually high, with some parts of south-east England potentially not dropping below 20C overnight. Across the country more broadly, overnight lows will likely settle between 15 and 19C. For context, typical late September nights in the UK see temperatures fall to between 7 and 11C. A night where the thermometer barely dips below 20C reads more like midsummer than early autumn.
This episode of warmth arrives as September itself is tracking significantly above normal. Through the 26th of the month, the Central England Temperature—the world's longest continuous temperature record, maintained across multiple locations in England—stands 2.6 degrees Celsius above the historical average. Every single month of 2026 has recorded above-average temperatures, and the year-to-date average is also running 2.6C higher than normal. For 2026 to avoid becoming one of the warmest years on record for the UK, the remaining months would need to be substantially colder than typical, a scenario the Met Office's latest three-month outlook suggests is unlikely. Their forecast for October through December points toward higher-than-normal chances of a mild autumn and early winter ahead.
Notable Quotes
It would need to be much colder than normal during the rest of the year for 2026 to not be one of the warmest on record for the UK— BBC Weather analysis
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