Winter and dark season speed limits will be introduced nationwide by Friday. But there are some exceptions.

The road speed limits will be changed to the winter speed limits and the dark season speed limits by Friday, October 27th.
The main date for the changeover is Thursday, October 26, but the Centers for Economic Development, Transport and the Environment (ELY) may begin making changes as early as Monday, October 23, if local conditions require.
The speed limit is reduced to 80 kilometers per hour in many places and 70 kilometers per hour in some places. Highway speed limits are reduced to 100 kilometers per hour.
“However, high levels of road safety or low traffic volumes allow for some exceptions to the main winter speed limits. For example, the 100 km/h speed limit may remain in force on roads where there is a crash barrier separating the two directions of traffic,” Tuomas Österman, a traffic management expert at the Finnish Road Administration, said in a statement.
As in previous years, Fintraffic can maintain the higher speed limits on variable-speed highways until the end of November, weather and conditions permitting. This means, for example, that the 120 km/h limit can remain in force during the month of November in good daytime driving conditions.
In early April, when the days are longer and driving conditions are better, the speed limit will return to normal.