I will be in Budapest soon, including Aug 19/20. What will be closed? I am mostly interested in finding out closures of restaurants, cafes, and thermal baths.
I was in Prague on a public holiday in July and, sadly, many good cafes and restaurants were closed.
I'm actually jealous. In 15 years of traveling to Bpest, I have never managed to be there for St Stephen's day. All sorts of stuff going on in town! Just remember most museums are closed on Mondays, regardless of holidays. As for the bath houses, you are in luck http://m.szechenyibath.hu/news/special-opening-hours-for-20-august
And for restaurants, I would contact them in advance and ask. But I suspect it will not be hard to find good food.
