Early Sunday morning brought the first frost to many parts of the country, the Finnish Meteorological Institute (FMI) reports. The coldest was in Salla, eastern Lapland, where the mercury sank to -4.7 degrees Celsius.
Sub-zero nights have been recorded since August in the northern and central parts of the country, but now they have reached nearly to the south coast.
For example, in Vihti, Uusimaa, some 50 km from Helsinki, the night-time low was -1.9 degrees. In Lappeenranta, South Karelia, a reading of–2.3 was measured at the Konnunsuo weather station, near the Russian border.
However, the northern airflow will give way to warmer air moving into Finland from the west this week.
Increasing cloudiness is expected during the day on Sunday, but southern and central parts of the country should remain dry, although there is a chance of isolated showers.
Up north, rain in the far northwestern arm will move to other parts of Northern Lapland. Central and southern parts of Lapland will be mostly dry.
Daytime temperatures range between 10 and 14 degrees in southern and central part of the country and 7-12 degrees in Lapland.
Warmer week ahead
Milder conditions will return early Monday as a warmer air mass flows into Finland from the west. Overnight lows will be around 6-8 degrees on the south coast, rising to around 16-17 on Monday, slightly chillier towards the east. Temperatures remaining in the single digits in northern Lapland, with a chance of rain through Wednesday.
Daytime temperatures are set to rise again, as the warm air mass is forecast to remain over Finland next week. At least in the south, temperatures should be in the upper teens, even approaching 20 degrees through Saturday.