What Week: Week 52
Find the calendar dates covered by any ISO week number.
ISO Week 52 of 2026 runs from December 21 to December 27, 2026, with roughly 0 ISO weeks remaining in the year after it. ISO 8601 weeks always run Monday through Sunday and belong to the year containing that week's Thursday, which is why the first few days of January sometimes belong to the final week of the previous year. Christmas Eve, Christmas, Boxing Day, Kwanzaa, the First Day of Winter fall within this week in 2026. Next year, 2027, the same week number runs from December 27 to January 2, 2028 instead, since the exact dates shift slightly every year.
As of October 1, 2026, 12:19 PM (America/New York).
Position in the Year
Week 52 falls in the second half of the year, roughly 100% of the way through 2026's 52-53 ISO weeks.
Quarter Overlap
This week sits in calendar Q4, based on its Monday (December 21).