Date facts
Sunday, December 21, 2025
December 21, 2025 is day 355 of 365, in ISO week 51. There are 10 days left in 2025 after this date.
Weekday
Sunday
Calendar weekday
Day of year
355
of 365
ISO week
51
Week-year 2025
Days remaining
10
In 2025
Weeks start on Monday and use ISO week numbers. Sunday is week 51 of 2025.