Those disappointed by this year’s grey summer may be able to enjoy a sunny spell in October – with a possible high of 73F (23C) next week.
Temperatures are expected to be unseasonably warm next month, particularly in southern England.
Grahame Madge, Met Office meteorologist, said: “We are anticipating a warmer than average end to September, which will bleed into October.
“We’re looking at temperatures of six or seven degrees above average.
“There won’t be a heatwave but a warmer than average spell is certainly on the cards, with the warmest temperatures likely to be in Southampton, Hampshire, East Anglia and London, which will see the low 20s next week.”
Temperatures could reach as high as 23C next Tuesday, 22C on Wednesday, 19C on Thursday and 20C on Friday – hitting 21C at the weekend.
The maximum and minimum average temperatures for the UK in October are 13.8C and 6.4C, respectively – and 14.7C and 7.5C for southern England.
However, the mercury is unlikely to hit the highest-ever October temperature recorded – 29.9C in Gravesend, Kent, in 2011.
Meanwhile, Storm Agnes has hit parts of Wales and Ireland with gale-force winds, floods and power outages.
Winds reached speeds of 68mph in Aberdaron, Wales, 58mph in Glenanne, Northern Ireland, and 54mph in Camborne, Cornwall. A high of 79mph winds was recorded in Capel Curig, a village in Wales, on Wednesday evening.
Storm Agnes triggered a series of Met Office yellow weather warnings for wind and rain across the UK, with forecasts of flooding, travel disruption and power outages.
Flood warnings were in force in parts of England, Scotland and Wales, with a red alert in Keswick, and amber warnings in parts of Devon and Cornwall, and along the Carmarthenshire, Cardigan Bay and Anglesey coastline.
A woman had to be rescued from her car in County Londonderry, Northern Ireland, after it was trapped by floodwater.
An Easyjet plane was unable to land in Belfast on Wednesday afternoon and the airline told the Belfast Telegraph that the difficulty was due to “winds gusting outside the limits of the aircraft”.
Around 135 properties on the Isles of Scilly, in the south-west of England, experienced power outages for just under four hours earlier on Wednesday, according to National Grid.
Ireland, where Agnes first made landfall, saw flooding and travel disruption, with fallen trees blocking roads and flights and ferries also being affected.
A roof was blown off a building in County Cork.
The Royal National Lifeboat Institution had warned of “dangerous conditions” on the coasts, and the Humber Maritime Rescue Coordination Centre warned people to avoid selfies in the stormy weather.
Alerts triggered by Storm Agnes included a wind warning until 7am on Thursday, which was cancelled early on Thursday morning.
The warning stretched across Scotland, Northern Ireland and Wales, as well as the south-west of England, the West Midlands and most of the north of England.
There were also rain warnings for much of Scotland until Thursday at 3am.
The storm has “decayed rapidly” as it continues to move away from the UK, the Met Office said.