Britons are being warned of "cold Arctic air" sweeping across the UK which could cause temperatures to drop as low as 0C.
The latest weather maps show temperatures plummeting to single figures due to the strong winds.
The Met Office said average temperatures will range between 4C and 6C, with frost likely to develop on Thursday evening.
Forecasters say the coldest night this week is set to be Thursday.
Britons are being warned of "cold Arctic air" sweeping across the UK which could cause temperatures to drop as low as 0CWXCHARTSMet Office spokesperson Jonathan Vautrey said waking up on Friday morning "could be quite a shock to the system".
Vautrey said: "Many of us will see temperatures in the mid-teens – around 13 to 14C – whereas normally at this time of year it would be at least 16 to 18C, if not closer towards 19 to 20C in the far South East, places like London".
He added temperatures are likely to feel "more like single figures" as strong winds strike.
"For people waking up on Friday morning it could be quite a shock to the system as they’re walking out of the door," he said.
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Frost is also expected to appear overnight on Thursday with temperatures dropping to 0C in Scotland, 1C in north east England and 4C in the midlands and south east.
Netweather forecaster, Nick Finnis said: "After a chilly night, another cool and showery day on Thursday, sunny spells between the showers, though the wind should ease from the north, showers easing in the north too.
"With winds easing and skies clearing, Thursday night could be the coldest night of the week, with temperatures early Friday falling into low single figures widely, low enough to bring a touch of frost in sheltered areas in the north."
Warmer air is expected to push back against the cold blast on Friday as temperatures rise.
Frost is also expected to appear overnight on Thursday with temperatures dropping to 0C in Scotland, 1C in north east England and 4C in the midlands and south east
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Temperatures are set to climb back up to 13C by Friday afternoon.
Met Office forecaster Craig Snell said Britain's first "autumn chill" has hit.
He said: "As we go through into Tuesday and Wednesday and beyond, we will start to see even cooler air begin to move in from the Arctic.
"Our first autumn chill of the season is coming our way into the middle part of the week. It will bring temperatures around the mid-teens by day and by night, some of us will be falling into the low and mid single figures."
