Week 1 of 2027: Dates
Week 1 of 2027 starts on Monday, January 4, 2027 and ends on Sunday, January 10, 2027. It falls in January, in the first quarter of 2027.
The days of week 1, 2027
| Day | Date | Day of year | US federal holiday |
|---|---|---|---|
| Monday | January 4, 2027 | Day 4 | |
| Tuesday | January 5, 2027 | Day 5 | |
| Wednesday | January 6, 2027 | Day 6 | |
| Thursday | January 7, 2027 | Day 7 | |
| Friday | January 8, 2027 | Day 8 | |
| Saturday | January 9, 2027 | Day 9 | |
| Sunday | January 10, 2027 | Day 10 |
Other days in this week: Epiphany, Orthodox Christmas, 2nd January Bank Holiday (Scotland), Isra and Mi'raj.
ISO and US week numbers
Week 1 covers days 4 to 10 of 2027. US calendars start the week a day earlier, on Sunday, January 3. On that count the same Monday is in week 2 of 2027, one off from the ISO number. To check it in Excel or Google Sheets, =ISOWEEKNUM(DATE(2027,1,4)) returns 1 and =WEEKNUM(DATE(2027,1,4)) returns 2.
Week 1 by year
| Year | Monday | Sunday |
|---|---|---|
| 2027 | January 4, 2027 | January 10, 2027 |
| 2028 | January 3, 2028 | January 9, 2028 |
| 2029 | January 1, 2029 | January 7, 2029 |
| 2030 | December 31, 2029 | January 6, 2030 |
| 2031 | December 30, 2030 | January 5, 2031 |
| 2032 | December 29, 2031 | January 4, 2032 |
This page shows the next week 1 that has not ended yet. ISO weeks start on Monday, and week 1 contains the year's first Thursday.
Week 1 questions
When does week 1 of 2027 start?
On Monday, January 4, 2027. It ends on Sunday, January 10, 2027, seven days later.
Does every year have a week 1?
Yes. Every ISO year has weeks 1 to 52, and only some have a week 53.
Related pages
Cite this page
APA: ClockTotals. (2026, October 18). Week 1 of 2027: Dates. https://clocktotals.com/week-number/1/
MLA: “Week 1 of 2027: Dates.” ClockTotals, 18 Oct. 2026, clocktotals.com/week-number/1/.
Link (HTML): <a href="https://clocktotals.com/week-number/1/">Week 1 of 2027: Dates</a>