Week 21, 2026
May 18–24, 2026
Monday May 18 – Sunday May 242026-W21Days 138–144
The seven days
| Date | ISO week date | Day of year | US week | Islamic date (computed) | Holidays and other dates |
|---|---|---|---|---|---|
| Mon, May 18 | 2026-W21-1 | 138 | 21 | 1 Dhu al-Hijjah 1447 AH | Victoria Day (Canada (federal)) |
| Tue, May 19 | 2026-W21-2 | 139 | 21 | 2 Dhu al-Hijjah 1447 AH | |
| Wed, May 20 | 2026-W21-3 | 140 | 21 | 3 Dhu al-Hijjah 1447 AH | |
| Thu, May 21 | 2026-W21-4 | 141 | 21 | 4 Dhu al-Hijjah 1447 AH | |
| Fri, May 22 | 2026-W21-5 | 142 | 21 | 5 Dhu al-Hijjah 1447 AH | |
| Sat, May 23 | 2026-W21-6 | 143 | 21 | 6 Dhu al-Hijjah 1447 AH | |
| Sun, May 24 | 2026-W21-7 | 144 | 22 | 7 Dhu al-Hijjah 1447 AH |
About week 21
In US numbering, where weeks start on Sunday and the week of January 1 is week 1, Monday to Saturday are US week 21 and Sunday US week 22.
Holidays this week: Victoria Day on Mon, May 18 in Canada (federal). 1 Dhu al-Hijjah 1447 AH falls on Mon, May 18 by the Umm al-Qura calendar (computed). All weeks of 2026 lists the neighbouring weeks.
Week 21 in other years
| Year | Week 21 runs |
|---|---|
| 2024 | Mon, May 20 – Sun, May 26 |
| 2025 | Mon, May 19 – Sun, May 25 |
| 2026 | Mon, May 18 – Sun, May 24 |
| 2027 | Mon, May 24 – Sun, May 30 |
| 2028 | Mon, May 22 – Sun, May 28 |
| 2029 | Mon, May 21 – Sun, May 27 |
In 2027, week 21 runs Mon, May 24 – Sun, May 30: 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 21 falls between May 17 and May 24.
By the end of week 21, 144 days of 2026 have passed (39.5% of the year), and 32 ISO weeks of 2026 remain. The week falls in Q2.
Writing week 21
ISO 8601 writes this week as 2026-W21 (basic format 2026W21), from 2026-W21-1 on Monday to -7 on Sunday. The week number page shows the spreadsheet and Python formulas that give these numbers.