Week 12, 2026
March 16–22, 2026
Monday March 16 – Sunday March 222026-W12Days 75–81
The seven days
| Date | ISO week date | Day of year | US week | Islamic date (computed) | Holidays and other dates |
|---|---|---|---|---|---|
| Mon, Mar 16 | 2026-W12-1 | 075 | 12 | 27 Ramadan 1447 AH | |
| Tue, Mar 17 | 2026-W12-2 | 076 | 12 | 28 Ramadan 1447 AH | St Patrick's Day (UK: Northern Ireland); Saint Patrick's Day (Ireland) |
| Wed, Mar 18 | 2026-W12-3 | 077 | 12 | 29 Ramadan 1447 AH | |
| Thu, Mar 19 | 2026-W12-4 | 078 | 12 | 30 Ramadan 1447 AH | |
| Fri, Mar 20 | 2026-W12-5 | 079 | 12 | 1 Shawwal 1447 AH | Vernal Equinox Day (Japan); Eid al-Fitr |
| Sat, Mar 21 | 2026-W12-6 | 080 | 12 | 2 Shawwal 1447 AH | Human Rights Day (South Africa); Hari Raya Puasa (Singapore); Nowruz 1405 |
| Sun, Mar 22 | 2026-W12-7 | 081 | 13 | 3 Shawwal 1447 AH |
About week 12
In US numbering, where weeks start on Sunday and the week of January 1 is week 1, Monday to Saturday are US week 12 and Sunday US week 13.
Holidays this week: St Patrick's Day on Tue, Mar 17 in UK: Northern Ireland; Saint Patrick's Day on Tue, Mar 17 in Ireland; Vernal Equinox Day on Fri, Mar 20 in Japan; Human Rights Day on Sat, Mar 21 in South Africa; Hari Raya Puasa on Sat, Mar 21 in Singapore. The March equinox is on Fri, Mar 20 at 14:46 UTC. 1 Shawwal 1447 AH falls on Fri, Mar 20 by the Umm al-Qura calendar (computed). Also this week: Eid al-Fitr on Fri, Mar 20 (1 Shawwal, Umm al-Qura (computed); announced locally); Nowruz 1405 on Sat, Mar 21 (Persian New Year, 1 Farvardin). All weeks of 2026 lists the neighbouring weeks.
Week 12 in other years
| Year | Week 12 runs |
|---|---|
| 2024 | Mon, Mar 18 – Sun, Mar 24 |
| 2025 | Mon, Mar 17 – Sun, Mar 23 |
| 2026 | Mon, Mar 16 – Sun, Mar 22 |
| 2027 | Mon, Mar 22 – Sun, Mar 28 |
| 2028 | Mon, Mar 20 – Sun, Mar 26 |
| 2029 | Mon, Mar 19 – Sun, Mar 25 |
In 2027, week 12 runs Mon, Mar 22 – Sun, Mar 28: 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 12 falls between March 15 and March 22.
By the end of week 12, 81 days of 2026 have passed (22.2% of the year), and 41 ISO weeks of 2026 remain. The week falls in Q1.
Writing week 12
ISO 8601 writes this week as 2026-W12 (basic format 2026W12), from 2026-W12-1 on Monday to -7 on Sunday. The week number page shows the spreadsheet and Python formulas that give these numbers.