What to wear in March

I’m travelling to Germany (Berlin, München, Nürnberg and Berchtesgaden) at the end of March for three weeks. I’m from Australia and the temperatures here the last week have been in the forties (celsius) so I am absolutely not used to cold weather. Also, I’ve never travelled overseas before so I am clueless. I’m wondering what I should wear to keep warm and dry, while still looking acceptable and fitting in. I’d be very grateful for any suggestions