How many days until December 21?
See the exact days, hours, minutes, and seconds remaining until December 21. The countdown updates every second using your local timezone.
December 21 date facts
Key calendar details for the next occurrence of December 21.
About December 21
December 21 is the 355th day of the year in the Gregorian calendar (356th in a leap year), situated in early winter in the Northern Hemisphere in the Northern Hemisphere. It falls in the fourth quarter, associated with seasonal transitions and year-end planning.
December comes from Latin decem meaning ten, originally the tenth month.
For planning today, December 21 is a fixed annual date: it occurs on the same calendar date every year and is always 1 day after December 20 and 1 day before December 22. That makes the countdown predictable for seasonal events and deadlines.
Why track how many days until December 21?
A fixed early-spring anchor used for personal, academic, and business planning.
No verified international observances are listed specifically for December 21. This section will be updated as curated data becomes available.
What’s special about December 21?
Important observances, events, traditions, and historical milestones associated with December 21.
How the countdown works
We create December 21 at 00:00 in your local timezone for this year. If that moment has already passed, we roll to December 21 next year.
All calculations use your device clock and local timezone, so the countdown hits zero exactly when December 21 starts where you are.
Remaining milliseconds are converted to days, hours, minutes, and seconds. Values never go negative and update every second.
Leap years are handled automatically by the calendar — the interval from December 21 to next December 21 is 365 or 366 days as appropriate.
If today is after December 21, the timer counts toward next year’s December 21 and shows how many days ago the last one occurred.
The timer is scoped to this component, accessible, and works on mobile without external libraries.
Related countdown dates
Nearby dates and same-day links around December 21.
December 21 countdown FAQ
The countdown above shows the exact days, hours, minutes, and seconds until the next December 21 in your local timezone.
Divide the remaining days by seven. The Date Facts section also shows weeks remaining.
December 21 falls on a different weekday each year. See Date Facts for this occurrence’s weekday.
We take the next December 21 at 00:00 local time, subtract the current local time, and convert the difference into days, hours, minutes, and seconds.
Yes. It uses your device’s local timezone, so it reaches zero precisely when December 21 begins for you.
It automatically counts down to December 21 of the following year and shows how many days ago the last December 21 occurred.
December 21 does not have a major widely recognized international observance, but it is part of early winter in the Northern Hemisphere and commonly used for seasonal planning.
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