The UK is on course for the warmest October ever, despite torrential rain and heavy floods, forecasters said yesterday.
At 13.6C (56.5F), this month's average temperature is the highest since records began in 1659. The previous record of 13C (55.4F) was set in 1969 and the average temperature for October would usually be around 10.5C (51F).
"It's quite extraordinary," said Steve Randall, national forecaster at the meteorological office.
"We've had exceptionally mild weather, considerably warmer than September. We are on course for an all time record, and temperatures of 20C (68F) are on the cards for spots in eastern England."
The existing record for October 30 is 19.4C (67F), set at Reading in 1927.
But Mr Randall said that high temperatures had been matched by high rainfall, around one and a half times the usual level for October.
"Winds coming in from the south and south-west are bringing in warmer air from over the Atlantic," he said.
Today and tomorrow will remain warm with some rain, but the autumn heatwave is likely to reach an abrupt end as November begins, with parts of the country seeing their first frosts.
Scientists have found that plants are flowering earlier than they used to and one study suggested that oak trees are coming into leaf in Surrey three weeks earlier than they did in the 1950s.
Simon Tett of the met office's Hadley centre for climate prediction and research said: "Our climate models tell us we would expect to see milder winters and warmer and probably drier summers, but more rainfall overall."