May 2, 2018 World Tuna Day
May 3, 2018 World Press Freedom Day
May 3, 2018 National Day of Prayer
May 4, 2018 Kent State Shootings Remembrance
May 4, 2018 Kentucky Oaks
May 4, 2018 Rhode Island Independence Day
May 5, 2018 Cinco de Mayo
May 5, 2018 Kentucky Derby
May 5, 2018 National Explosive Ordnance Disposal (EOD) Day
May 6, 2018 National Nurses Day
May 8, 2018 Time of Remembrance and Reconciliation for Those Who Lost Their Lives during the Second World War
May 8, 2018 World Ovarian Cancer Day
May 8, 2018 Victory in Europe Day
May 8, 2018 Primary Election Day
May 10, 2018 Ascension Day
May 10, 2018 Confederate Memorial Day
May 10, 2018 Confederate Memorial Day
May 11, 2018 Native American Day
May 11, 2018 Military Spouse Appreciation Day
May 12, 2018 World Migratory Bird Day
May 12, 2018 International Nurses Day
May 13, 2018 Mother's Day
May 15, 2018 International Day of Families
May 15, 2018 Peace Officers Memorial Day
May 16, 2018 Ramadan starts
May 17, 2018 World Information Society Day
May 18, 2018 National Defense Transportation Day
May 19, 2018 Armed Forces Day
May 19, 2018 Preakness Stakes
May 20, 2018 World Autoimmune Arthritis Day
May 21, 2018 World Day for Cultural Diversity for Dialogue and Development
May 22, 2018 International Day for Biological Diversity
May 22, 2018 National Maritime Day
May 22, 2018 Harvey Milk Day
May 23, 2018 International Day to End Obstetric Fistula
May 23, 2018 Emergency Medical Services for Children Day
May 25, 2018 African Liberation Day
May 25, 2018 National Missing Children's Day
May 27, 2018 Trinity Sunday
May 28, 2018 Memorial Day
May 28, 2018 Jefferson Davis' Birthday
May 29, 2018 International Day of United Nations Peacekeepers
May 29, 2018 Day of Vesak
May 31, 2018 Corpus Christi
May 31, 2018 World No Tobacco Day