What Day: December 21
Find the day of the week for any date of the year.
December 21 this year (2026) falls on a Monday. It's day 355 of the year, with 10 days left afterward, sits in Q4 (Winter), and falls under the zodiac sign Sagittarius in Western astrology. Because of how leap years shift the calendar, a date's day-of-week doesn't repeat on a fixed yearly schedule. December 21 will next fall on a Monday again in 2037. Within December, this is day 21 of 31, roughly 68% through the month. Overall, that's roughly 97% of the way through the year.
As of October 1, 2026, 12:19 PM (America/New York).
A Decade Ago
December 21, 2016 fell on a Wednesday, a useful reference point if you're comparing how a recurring event has shifted across the week over the years.
Half a Year Away
Roughly six months from December 21 is June 21, which falls in summer and lands on a Sunday this year.
Nearby Dates
Check the day of the week for the date just before or after December 21 using the links below.