I see temps around 65 or so during the day. I'm in Dallas, and generally LOVE it when it dips that low here. But, I'm concerned as I wasn't planning on bringing an every day jacket--just a goretex lightweight rain coat in bright yellow. I suppose it could serve as a jacket, but I don't imagine bright yellow being the latest fashion trend right now! I've been so careful to not over pack, and I really don't want to take two jackets!
Here's the 10-day forecast for Munich: Munich weatherIf that's not close to where you're going in Bavaria, use that site to input another name, has to be a fairly large city.
Take a wind breaker, leave the Goretex home and buy a cheap umbrella there. In any case you will also need a warmth layer - sweater or fleece. The weather is changeable this time of year.