Wikipedia:Selected anniversaries/Holidays and observances

This is a more-or-less complete list of holidays and observances that may be included in any of the subpages of Selected anniversaries. The purpose of this list is to help editors keep track of when the days should be listed, especially those whose dates vary from year to year. Note that the listings may be omitted from the various subpages because of article quality concerns.

Moveable days
Listed in order of the first possible day.

Islamic holidays
The Islamic calendar is shorter than the Gregorian year, so each observance will occur earlier in the Gregorian calendar every year by about 10–12 days.