Mother’s Day [Not a public holiday] Calendar When: May 8, 2016 all-day 2016-05-08T00:00:00-05:00 2016-05-09T00:00:00-05:00 Where: USA Holiday 2nd Sunday in May. Not a public holiday. Not a public holiday, but a legal national holiday observed on the second Sunday in May in the United States Information provided by www.officeholidays.com