Hello omillan78
The ZVV-holidays are:
The following are considered public holidays: January 1st and 2nd, Good Friday, Easter Monday, Ascension Day, Whit Monday, May 1st, August 1st, December 25th and 26th. (T 651.8, 3.9.11, Translated by Google).
May 1st is not a holiday in national tariffs.
Kind regards
Danhiel