Britain's record-breaking autumn heatwave is expected to come to an abrupt end today, with temperatures plummeting and strong winds ripping across northern regions.
Forecasters predict the mercury will begin to drop in all parts of the UK, before the weather becomes even fresher and unsettled as the week progresses.
The mini-heatwave that baked the majority of the UK last week continued yesterday with highs of 28C (82.4F) in Coningsby, Lincolnshire.
But by the end of the week temperatures will peak at a much cooler 14C (57.2F), weather experts said.
Billy Payne, a forecaster with MeteoGroup, the weather division of the Press Association, said: "It is looking cooler and more unsettled from today with a lot of cloud over southern England and and a few spots of rain especially in the west.
"The north will have some blustery showers and it will be quite windy with local gales in the northern isles. Temperatures in some places will drop by as much as 10C, but London could still see highs of 20C."
Much of the UK will see showers by Thursday, with longer spells of rain, continuing strong winds and some thunderstorms across western Scotland and north-west England.
Parts of Scotland could even be hit by frost, with temperatures of just 3C (37.4F) or 4C (39.2) expected on Friday night.
Mr Payne added: "It is now very unlikely that we will see the temperatures we have had over the past week until early summer next year."
The UK's hottest day of 2011 was June 27 when a temperature of 33.3C (91.9F) was recorded at the Olympic Park in London.
South West Trains said it would be operating a "leaf fall" timetable until December 10 on some routes, with some services departing a few minutes earlier.
The company said leaves falling on the rails are crushed by passing trains, forming a slippery film which makes it harder for trains to accelerate away from stations and meaning drivers have to approach station stops more slowly than normal.
Network Rail runs special rail-cleaning trains but these can only reduce and not completely eliminate the problem, South West Trains said on its website.