Week 4, 2026
January 19–25, 2026
Monday January 19 – Sunday January 252026-W04Days 19–25
The seven days
| Date | ISO week date | Day of year | US week | Islamic date (computed) | Holidays and other dates |
|---|---|---|---|---|---|
| Mon, Jan 19 | 2026-W04-1 | 019 | 4 | 30 Rajab 1447 AH | Birthday of Martin Luther King, Jr. (United States (federal)) |
| Tue, Jan 20 | 2026-W04-2 | 020 | 4 | 1 Sha'ban 1447 AH | |
| Wed, Jan 21 | 2026-W04-3 | 021 | 4 | 2 Sha'ban 1447 AH | |
| Thu, Jan 22 | 2026-W04-4 | 022 | 4 | 3 Sha'ban 1447 AH | |
| Fri, Jan 23 | 2026-W04-5 | 023 | 4 | 4 Sha'ban 1447 AH | |
| Sat, Jan 24 | 2026-W04-6 | 024 | 4 | 5 Sha'ban 1447 AH | |
| Sun, Jan 25 | 2026-W04-7 | 025 | 5 | 6 Sha'ban 1447 AH |
About week 4
In US numbering, where weeks start on Sunday and the week of January 1 is week 1, Monday to Saturday are US week 4 and Sunday US week 5.
Holidays this week: Birthday of Martin Luther King, Jr. on Mon, Jan 19 in United States (federal). 1 Sha'ban 1447 AH falls on Tue, Jan 20 by the Umm al-Qura calendar (computed). All weeks of 2026 lists the neighbouring weeks.
Week 4 in other years
| Year | Week 4 runs |
|---|---|
| 2024 | Mon, Jan 22 – Sun, Jan 28 |
| 2025 | Mon, Jan 20 – Sun, Jan 26 |
| 2026 | Mon, Jan 19 – Sun, Jan 25 |
| 2027 | Mon, Jan 25 – Sun, Jan 31 |
| 2028 | Mon, Jan 24 – Sun, Jan 30 |
| 2029 | Mon, Jan 22 – Sun, Jan 28 |
In 2027, week 4 runs Mon, Jan 25 – Sun, Jan 31: 2026 has 53 weeks, so the same number comes 371 days later, 6 days later in the calendar. Over the 400-year cycle, the Monday of week 4 falls between January 19 and January 25.
By the end of week 4, 25 days of 2026 have passed (6.8% of the year), and 49 ISO weeks of 2026 remain. The week falls in Q1.
Writing week 4
ISO 8601 writes this week as 2026-W04 (basic format 2026W04), from 2026-W04-1 on Monday to -7 on Sunday. The week number page shows the spreadsheet and Python formulas that give these numbers.