Are city tours and excursions operated on Sundays and national holidays?

All regular and private tours run on Sundays at no extra cost. On national holidays: May 3, November 11 – private tours available, but regular scheduled-departure city tours are not operated. January 1, May 1, August 15, November 1, December 24, 25, 26, 31 – no scheduled-departure tours are operated, but we can attempt to arrange private tours, though their prices will probably be higher.
Please be informed that most of the museums in Poland are closed on Mondays.