An exceptionally warm night embraced Helsinki on Tuesday. Kaisaniemi saw temperatures drop only to 16.9°C at 2:20 AM.

By 5 AM, the temperature rose to 17.4°C, an unusual event in the city’s climate history.

“Such warmth occurs less often than once every 30 years,” reported Vendi Pelkonen, a meteorologist at the Meteorological Institute.

To put it in context, the long-term average for nighttime temperatures in Kaisaniemi is just 7.6°C during this season.

Southern and central Finland also experienced this exceptional warmth, including Oulu, with 12.3°C at the airport.

Even at Helsinki-Vantaa Airport, the temperatures remained above 15.5°C, defying the cold expectations of early autumn.

Just days earlier, the night before Sunday saw an unseasonal frost of -1.5°C at Helsinki-Vantaa.

The coldest spot was Saanatunturi in Lapland, where the temperature plummeted to -2.9°C.

The culprit behind this unusual warmth? Winds from the south and widespread cloud cover trapping the heat near the surface.

Wednesday and Thursday will also bring mild conditions, with temperatures ranging between 15–20°C in southern and central Finland.

However, rain will soon arrive from the west, cooling things down by Friday, with only 12°C forecasted by Sunday.

In Lapland, expect sleet or snow as temperatures drop again. The first snow has already fallen in Käsivarren.

This rare weather pattern will make way for cooler, wetter conditions, as autumn progresses across Finland.