Last month was the joint-fourth warmest September in the UK since records began, according to provisional data from the Met Office.
The mean average temperature across the month was 14.6C, slightly below the all-time high for September of 15.2C set in 2023 and 2006.
A spell of unseasonably warm weather towards the end of the month helped push 2026 up the rankings.
High pressure over southern parts of the country brought hot conditions to many areas in recent days, with temperatures peaking at 28.1C at Kew Gardens in London on September 29.
Last month’s average temperature of 14.6C equals the September figures for 2016 and 1949, and sits just behind the 14.7C measured in 2021.
Met Office climate information scientist Mike Kendon said: “Persistent warmth has been the theme of recent months and September is no different.
“While the month itself was unexceptional overall, when putting it into the context of the warm year we’ve had so far, this fits with the general pattern that we’re seeing of more frequent above average temperatures in the UK as our climate continues to change.”
September was the sixth month in a row when the mean average temperature was high enough to rank in the top 10.
This year has seen the UK’s seventh warmest April, the joint-third warmest May, the second warmest June, the second warmest July, the sixth warmest August, and now the joint-fourth warmest September.
Met Office temperature records begin in 1884.
The UK overall received slightly more rain than the long-term average for September, though this masks some notable differences across the country.
While Scotland, Wales and Northern Ireland all had above average amounts of rainfall, England received only 65% of what is expected for the month, with southern and eastern England remaining particularly dry.
Environment Agency chief executive Philip Duffy said: “September’s rainfall has been welcome, but a few weeks of unsettled weather is nowhere near enough to reverse the water deficits caused by a dry spring and record hot summer.
“We still need everyone to use a little less water to speed up the drought recovery and save more for our local rivers, farmers, and wildlife.”
“Drought is only over when groundwater, rivers, and reservoirs are back to normal levels – and that will take months of significant and sustained wet weather.
“In the meantime, the situation remains serious with drought-hit areas of England again seeing the least amount of rain over the month.
Most of England and all of Wales remain officially in drought, the exceptions being the North East, North West and Yorkshire.
Around 30 million people in England have restrictions on their use of water.
The national drought group continues to meet weekly to co-ordinate action and monitor risks across the country.
The group includes representatives of the Met Office, the Government, regulators, water companies, the National Farmers’ Union and the Canal & River Trust, along with anglers and conservation experts.
Reservoir storage in England stood at 56% last week, nearly 19 percentage points below the average for this time of year, according to the Environment Agency.
This year’s scorching weather saw parts of the country endure as many as five heatwaves, with the first in late May, followed by one in late June, two in July and one in mid-August.
The June heatwave prompted a rare red alert from the Met Office for extreme heat and saw temperatures peak at 38.0C on June 26 in Lingwood in Norfolk – a new record for the month.
An estimated 2,877 deaths in England were associated with the heatwaves in May and June, according to the UK Health Security Agency.
As the hot weather continued, England saw its driest July since data began, with only 7mm of rain measured, or 10% of the long-term average.
The most recent heatwave, in mid-August, saw temperatures climb as high as 38.2C at Hartpury College in Gloucestershire on August 13, making it the hottest day of the year.
