The climate in Germany is similar to that in northern China, with high latitude.

It's very warm indoors in Germany. If you are not outdoors for a long time, you don't need to wear too many layers

For example, most students wear underwear shirts in the classroom library, or add a thin sweater and a warm coat outside. It's usually not too cold to go back and forth by subway.

I didn't even wear thermal underwear in Ruhr last year, let alone woolen pants.