> Finns and Norwegians only are able to bike part of the year.

They very much bike all year round, even in the north where it regularly gets to -20C(-4F) in winter. Biking in snowy sub-freezing weather is really not a big deal as long as you maintain the bike paths as well as the streets.

Source: have lived there, everyone I knew had a bike they regularly used. The only time I can recall where people I knew who usually commuted by bike didn't do so was during an unusually heavy snowstorm. They instead had to walk about half a kilometer to/from where the city had managed to plow the streets and take a taxi. That was decades ago.