Almost all of Finland experienced subzero conditions on Wednesday night, according to the Finnish Meteorological Institute (FMI).
The mercury crept below the freezing point at most of the country's weather stations.
The coldest temperature measured in the south was -4.5 degrees Celsius and in Lapland the chilliest was -6.5 degrees.
However, the FMI said it does not expect the night-time freezing temperatures to continue daily, at least for the time being.
Hopefully mild winter ahead
Meanwhile, a seasonal outlook for Europe has forecast a relatively mild winter this year overall, but a cold spell could be in store before the end of the year, according to Carlo Buontempo, director of the Copernicus Climate Change Service.
The service issues seasonal forecast for the European Centre for Medium-Range Weather Forecasts (ECMWF).
Buontempo predicted that Europe will experience a colder, less windy weather period in November or December.
He said the weather phenomenon known as La Niña will prevail over the Pacific Ocean this year. La Niña is known to prompt westerly winds, bringing wetter and milder weather to Europe during the second half of winter.
Earlier this week, Finnish President Sauli Niinistö said that the country will persevere through a potentially difficult winter amid the energy crisis prompted by Russia's invasion of Ukraine. Milder weather this winter could potentially alleviate heating costs, which have been rising for months.
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