National days, ongoing national weeks and months, and global observances for December 31, 2026. Plus historical events and birthdays.
December 31, 2026 celebrates Leap Second Time Adjustment Day, plus 4 more. Leap Second Time Adjustment Day is listed as an observance title only. Some years scientists do not make adjustments. But, if they do, then it’s done on either June 30 or December 31.
Read the full story →Longer-running observances that include this date.
Universal Human Rights Month
Month
Bingo's Birthday Month
Month
Operation Santa Paws | December 1-24th
Month
Learn A Foreign Language Month
Month
National Drunk & Drugged Driving Prevention Month
Month
International Sharps Injury Prevention Awareness Month
Month
Spiritual Literacy Month
Month
Safe Toys And Gifts Month
Month
National Tie Month
Month
National Write A Business Plan Month
Month
Root Vegetables And Exotic Fruit Month
Month
Worldwide Food Service Safety Month
Month
Showing the first 12 — See all months for December.
