Strong winds felled trees and hampered traffic in many parts of southern Finland on Monday afternoon. Overnight there were heavy hailstorms and snowfall in other areas.
More than a thousand households in the Kanta-Häme and Kymenlaakso areas lost power.
In the North Karelia and Savo regions, trains ran late all day because of damage to safety equipment from lightning.
In the Helsinki area, local trains and trams ran late and a major thoroughfare, Sturenkatu, was partly closed during afternoon rush hour by a fallen tree. Most express ship departures across the Gulf of Finland were cancelled.
The Meteorological Institute issued a warning of dangerously strong winds in the south, along warnings of forest fire danger and strong ultra-violet radiation.
Winds were expected to diminish on Monday evening in most parts of southern Finland. On Tuesday, some parts of the south could receive their first significant rainfall in more than a month.
Meanwhile residents of the Tampere and Kangasala areas awoke to a white landscape created by a heavy hailstorm. Some hailstones measured up to several centimetres across.
On Sunday night, there was even snowfall in North Karelia and Lapland's north-western arm. On Monday night, frost was predicted in Northern Karelia and northern Lapland.