- National Physical Fitness and Sports MonthMay
- National Youth Traffic Safety MonthMay
- National Flower MonthMay
- Skin Cancer Awareness MonthMay
- Sudoku First Published as Number Place in Dell Puzzle MagazineMay, 1979
- May DayMay 1, 2023
- Mother Goose DayMay 1, 2023
- Whale Awareness Day (in Massachusetts)May 1, 2023
- Children’s Book WeekMay 2 - 8, 2023
- First Freedom RideMay 4, 1961
- Elizabeth Jane Cochran’s, Known as Nellie Bly, BirthdayMay 5, 1864
- Cinco de MayoMay 5, 2023
- Penumbral Lunar EclipseMay 5, 2023
- Cartoonist DayMay 5, 2023
- Eta Aquarids Meteor ShowerMay 5-6, 2023
- Space DayMay 6, 2023
- Beethoven’s Ninth Symphony PremiereMay 7, 1824
- World Password DayMay 7, 2023
- International Migratory Bird DayMay 8, 2023
- Victory in Europe Day (VE Day)May 8, 1945
- Central and Union Pacific Railroads MeetMay 10, 1869
- Richard Feynman’s BirthdayMay 11, 1918
- Edward Lear’s Birthday (Celebrated as Limerick Day)May 12, 1812
- Edward Lear’s LimericksMay 12, 1812
- Start of California Gold RushMay 12, 1848
- Frog Jumping DayMay 13, 2023
- Mother’s DayMay 14, 2023
- First permanent British colony Established in Jamestown, VirginiaMay 14, 1607
- Lewis & Clark Leave St. LouisMay 14, 1804
- Major Lassen Peak Volcanic EruptionMay 14, 1915
- National Windmill Day (Holland)May 14, 2023
- Mother’s Day CardsMay 14, 2023
- Mother’s Day PoemsMay 14, 2023
- L. Frank Baum’s BirthdayMay 15, 1856
- Discovery of Largest Prime Number Known to ManMay 15, 2004
- Sue Debuts at Field MuseumMay 17, 2000
- Karol Wojtyla Birthday (Pope John Paul II)May 18, 1920
- Major Mount St. Helens Volcanic EruptionMay 18, 1980
- Circus Day, Anniversary of First Ringling Brothers PerformanceMay 19, 1884
- Jerusalem DayMay 19, 2023
- Premiere of Star Wars: Episode IMay 19, 1999
- Charles Lindbergh Flies Historic Solo Nonstop Transatlantic FlightMay 20-21, 1927
- Amelia Earhart’s Atlantic CrossingMay 20, 1932
- Weights and Measures DayMay 20, 2023
- National Backyard Games WeekMay 21 - 27, 2023
- Most Powerful Earthquake of the 20th Century Struck ChileMay 22, 1960
- Margaret Wise Brown’s BirthdayMay 23, 1910
- World Turtle DayMay 23, 2023
- Cellophane Tape PatentedMay 27, 1930
- Golden Gate Bridge OpensMay 27, 1937
- Sojourner Truth Gives “Ain’t I Woman?” SpeechMay 28-29, 1851
- John F. Kennedy’s BirthdayMay 29, 1917
- Memorial DayMay 29, 2023
- First Daily American Newspaper PublishedMay 30, 1783
- President Woodrow Wilson Proclaims June 14 Flag DayMay 30, 1916
- National Spelling Bee WeekMay 30 - Jun 1, 2023
- First US copryight law passedMay 31, 1790
- Walt Whitman’s BirthdayMay 31, 1819
- Mark Felt Reveals Himself as Watergate’s Deep ThroatMay 31, 2005
