Former tropical Storm Zeta is set to batter the UK this week, with gale-force winds and torrential rain forecast.
There were "unusually warm" temperatures for November overnight into Monday but then the Met Office predicts a major U-turn.
Wind and rain is expected to persist through today and Tuesday for much of the nation, with cooler, sunnier weather moving in from Wednesday.
Met Office meteorologist Luke Miall said: "Some of that tropical air is still within the system - it's travelled a long way across the Atlantic over cool waters before reaching the UK but it's very, very moist air, so that's the reason it's putting these temperatures up overnight."
He went on to predict "sunshine and showers" for much of the nation over through to tomorrow, with temperatures in the mid-teens.
Yellow weather warnings are in place for rain which could cause travel disruption and potential power cuts in north-west England and the west coast of Wales down to Cardiff - reports Mirror Online.
Mr Miall said warm weather is expected in the south on Monday morning, but temperatures will drop through the day.
He warned of strong winds, especially in Scotland where gales could reach up to 75mph in the Hebrides.
He said: "There's good news on the horizon - we have got high pressure moving in which will dominate the whole country from Wednesday to Friday.
"We expect light winds and plenty of sunshine through the day on Wednesday, with the best of the sunshine in Wales.
"We're moving between the two types of typical autumn weather - from wet and windy at the start of the week to clear, cold, crisp and frosty weather by the end."
He added that following highs of 17C in the south on Monday morning and a gradual cooling over Tuesday, by Wednesday temperatures could drop to zero in rural northern areas, marking "potentially the first widespread frost of the year".
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The Met Office forecast for Liverpool said: "Monday will be a mostly wet and cloudy day with frequent showers blowing in from the west, which will become heavy at times, especially later in the day. Winds will remain blustery.
"Showers will continue for most of the night tonight, however they will clear away to the north towards sunrise along with the cloud cover. Winds will weaken throughout the night.
" Tomorrow, further cloud and showers will blow in from the west throughout the morning. It will, however, turn drier in the late afternoon, with some late sunny spells. Moderate westerly winds.
"Wednesday will turn cloudy for a time with a chance of a few showers but it will turn drier and sunnier later. The night will be cold under clear spells, although fog may develop quite widely.
"Mist and fog could be slow to clear on Thursday but some sunshine may develop later. As for Friday, it will continue to be dry with sunny spells once overnight mist and fog patches clear."
