FMI meteorologist Nina Karusto says: "It looks like the snow will continue in the south and will do so a surprisingly long time today."
In the southwest of the country, the precipitation is mainly in the form of rain, while around the capital region it's more of a messy, wintry mix of snow and rain.
Once the temperature rises the snow on the ground will change to slush or water, Karusto says.
Later in the day, the precipitation system will gradually move north towards areas of northern Ostrobothnia and Kajaani by Friday evening at the latest.
There are only isolated snow showers in Lapland, according to the FMI.
Temperatures in southern Finland are a degree or two above freezing, in Lapland temperatures range from -5 to -10 degrees Celsius. Temperatures in the rest of the country on Friday are a few degrees below zero Celsius.
Conditions will likely start to clear up late in the day on Saturday across much of the country, with only isolated snow showers. On Sunday the weather should improve even further, FMI says.
The institute says that driving conditions in eastern and central areas will likely be slippery at least through Saturday.