December closes the year with 124 national days and holidays on Calendar.cx, headlined by Christmas Eve (Dec 24) and Christmas Day (Dec 25) — observed by billions worldwide. World AIDS Day opens the month on December 1, National Pearl Harbor Remembrance Day falls on December 7, and National Cookie Day is December 4. Festivus (Dec 23), made famous by Seinfeld, has earned its place as a genuine pop-culture holiday. Bacon Day (Dec 30) and New Year's Eve (Dec 31) close out the year. December also encompasses Hanukkah (dates vary), Kwanzaa (Dec 26–Jan 1), and the Winter Solstice (around Dec 21). Browse all 124 December holidays below.