I've just discovered that my trip to Hamburg includes Ascension Day which this year is Thursday May 14th.
I gather that this is taken more seriously in Catholic than Protestant parts of the country, but are any changes to shop opening times and train timetables likely?
This is a national holiday, so all stores will be closed in Germany. It is also Fathers' Day in Germany.
Museums, etc. should all be open though. Train schedules will run on a Sunday schedule.
You can try to find a tour which joins a team going Boßeln. This is a sport only performed in Northern Germany plus few neighbors and at every (!) weather. It is so local that Wikipedia does not have an English page for it. Other regions might have a similar sport with different names.
Oh, our farm does this every fall! It's super fun. But be aware that it's often a game that involves a lot of alcohol.
Yes, it's a public holiday. A great day to do things like renting a boat or canoe or SUP on the Alster if the weather cooperates (not sure how many operators will be open, but it's easy to check). You can visit lots of museums and attractions. But yes, schools and shops will be closed. The S-Bahn and such shouldn't be a problem.
