2021-W52
Week 52, 2021
Monday, December 27, 2021 – Sunday, January 2, 2022
This ISO week spans into 2022 (ends January 2, 2022).
Monday–Sunday
Sunday–Saturday convention on days in this range
Days in this week
| Weekday | Date | Day of year | Month | US week |
|---|---|---|---|---|
| Monday | December 27, 2021 | 361 | Calendar | 53 |
| Tuesday | December 28, 2021 | 362 | Calendar | 53 |
| Wednesday | December 29, 2021 | 363 | Calendar | 53 |
| Thursday | December 30, 2021 | 364 | Calendar | 53 |
| Friday | December 31, 2021 | 365 | Calendar | 53 |
| Saturday | January 1, 2022 | 1 | Calendar | 1 |
| Sunday | January 2, 2022 | 2 | Calendar | 2 |
Week 52 of 2021
ISO week 52 of 2021 (2021-W52) runs Monday, December 27, 2021 through Sunday, January 2, 2022. The full range is Dec 27 – Jan 2, 2022. Days follow the ISO Monday–Sunday convention. The US week label for dates in this window is 53–2.
Federal holidays in this window: New Year's Day. This ISO week spans into 2022 (ends January 2, 2022). When a holiday shifts observance to a nearby weekday, the table shows the date offices actually close rather than the legal calendar date alone.
ISO vs US week labels
ISO weeks always start on Monday and end on Sunday. US week numbers on this site often follow a Sunday-start convention used in retail and broadcast schedules. Both labels appear on week pages so you can match internal reports that use either system. When the two disagree at year boundaries, the cross-year note on this page explains which label applies to each calendar day.
Day-by-day breakdown
The grid above lists all seven days with weekday names, calendar dates, and day-of-year numbers. That layout helps compare ISO week boundaries against month-end billing cycles or school weeks that start on Sunday. Each row links back to the parent year table for context. Payroll teams often map ISO weeks to pay periods even when checks are issued on a different weekday schedule.
Download an ICS calendar file for this week to import the date range into Outlook, Google Calendar, or Apple Calendar. The file contains one all-day event spanning Monday, December 27, 2021 through Sunday, January 2, 2022.
Navigate weeks and years
Use previous week and next week links to step through 2021 one ISO week at a time. Open the full 2021 week table to jump to any week number directly.
Printable yearly view
For a single sheet with all twelve months and week columns, download the 2021 yearly calendar PDF. Monthly detail with larger day cells is available from the monthly calendars hub when this week spans two different months.
Frequently asked questions
What dates are in week 52 of 2021?
ISO week 52 (2021-W52) runs Monday, December 27, 2021 through Sunday, January 2, 2022, Monday through Sunday. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.
What is the US week for this range?
Days in this ISO week map to US week 53–2 under the Sunday–Saturday convention. Individual days may differ near year boundaries. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.
Are there federal holidays this week?
New Year's Day. Observed federal dates are listed above with weekday labels. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.
Does this week cross calendar years?
ISO weeks can begin in the previous December or end in the next January. Note for this week: This ISO week spans into 2022 (ends January 2, 2022). The day table above shows each calendar date. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.
How do I add this week to my calendar app?
Download the ICS file from this page. It creates an all-day event covering Monday through Sunday for 2021-W52. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.