Week 4 2026: Jan 19 – Jan 25
When is week 4? The exact Monday–Sunday dates of ISO week 4 for every year from 2024 to 2032.
Week 4 of 2026 runs from Monday, Jan 19, 2026 to Sunday, Jan 25, 2026 (January). In 2027, week 4 runs from Monday, Jan 25, 2027 to Sunday, Jan 31, 2027. ISO week code: 2026-W04.
The seven days of week 4
| Date | ISO week date | Day of year | Holidays |
|---|---|---|---|
| Monday, January 19, 2026 | 2026-W04-1 | 19 | Martin Luther King Jr. Day (US) |
| Tuesday, January 20, 2026 | 2026-W04-2 | 20 | — |
| Wednesday, January 21, 2026 | 2026-W04-3 | 21 | — |
| Thursday, January 22, 2026 | 2026-W04-4 | 22 | — |
| Friday, January 23, 2026 | 2026-W04-5 | 23 | — |
| Saturday, January 24, 2026 | 2026-W04-6 | 24 | — |
| Sunday, January 25, 2026 | 2026-W04-7 | 25 | — |
Day-of-year numbers and common US and international holidays. Weekday digits in the ISO week date run 1 (Monday) to 7 (Sunday).
Week 4 dates by year
| Year | Week 4 starts (Mon) | Week 4 ends (Sun) | Month |
|---|---|---|---|
| 2024 | Monday, January 22, 2024 | Sunday, January 28, 2024 | January |
| 2025 | Monday, January 20, 2025 | Sunday, January 26, 2025 | January |
| 2026 | Monday, January 19, 2026 | Sunday, January 25, 2026 | January |
| 2027 | Monday, January 25, 2027 | Sunday, January 31, 2027 | January |
| 2028 | Monday, January 24, 2028 | Sunday, January 30, 2028 | January |
| 2029 | Monday, January 22, 2029 | Sunday, January 28, 2029 | January |
| 2030 | Monday, January 21, 2030 | Sunday, January 27, 2030 | January |
| 2031 | Monday, January 20, 2031 | Sunday, January 26, 2031 | January |
| 2032 | Monday, January 19, 2032 | Sunday, January 25, 2032 | January |
All weeks
Frequently asked questions
What month is week 4 in?
Week 4 typically falls in January. The exact dates shift by up to a few days from year to year because week 1 is anchored to January 4, not January 1.
How do I write week 4 as a week code?
The ISO code is the year plus W04 — for example 2026-W04, short form 26W04, or YYWW date code 2604. See week number formats.
Are these dates the same in every country?
Yes for ISO 8601 (Monday-start) numbering, which is what this table shows. US Sunday-start calendars can label the same days with a number one higher — see week start conventions.