Easter:

Holy Thursday: Closed
Good Friday: Closed
Easter Eve: Closed
Easter Sunday: Closed
Easter Monday: Closed

May:

May Day, May 1: Closed
Constitution Day, May 17: Closed
Ascension Day, May 26: Closed

Pentecost:

Whit Sunday, June 5: Closed
Whit Monday, June 6: Closed

Christmas and New Year's:

December 22 - January 2: Closed
The museum shop is open on December 22.