The first signs of winter are coming with overnight frosts and ice in places - and there could even be snow on the hills of Northern Ireland soon.
Pointing out that a marked change is expected this weekend from the current mild weather, the Met Office tweeted: "The clocks will be going back this weekend, but so are the temperatures!!"Today's weather forecast
Met Office chief meteorologist Laura Paterson said: "It will feel very cold this weekend, with strong winds bringing heavy showers to many parts.
"Northern-facing coastal areas will see the most frequent showers, while elsewhere will see more in the way of sunshine.
"These showers could contain hail and turn to snow on the high ground, mainly Scotland, Northern Ireland and perhaps northern England."
The Met Office said the maximum temperature today in Northern Ireland will be 13C.
But by tomorrow and Saturday, there will be scattered heavy showers, some with hail, with the low here expected to be around 2C.
It will feel much colder with chilling winds and some snow on the hills.
Met Office meteorologist John West described it as "a real change in feel from the rather mild weather due to high pressure in the UK and replaced by a strong northerly flow from the Arctic".
Temperatures of 16C in Aberdeen and 19C in Southampton yesterday will fall to 12C and 13C today, 7C and 10C tomorrow and 6C and 8C on Saturday.
Mr West said: "While the thermometers will be maxing out at about 6C it will feel colder in that strong northerly wind."
The difference will be felt in daytime temperatures.
It looks like Saturday will be the coldest day, with temperatures recovering slightly for Sunday and showers becoming more confined to eastern areas.
Stein Connelly of Transport Scotland said: "Snow, sleet and ice look set to move into parts of Scotland at the end of this week, particularly over higher routes.
"Our operating companies have already started their winter services and will closely monitor the trunk road network, providing appropriate treatments where necessary.
"We encourage motorists to plan their journeys ahead of time, follow police travel advice and drive to the conditions."