ISO week 2026-W13

Week 13, 2026

Monday, March 23 – Sunday, March 29, 2026

ISO week 13 of 2026 (2026-W13) runs from Monday, March 23, 2026 to Sunday, March 29, 2026.

This week ended 29 weeks ago. The current week is week 42, 2026.

The 7 days of week 13

Dates in week 13, 2026
Day	Date	Day of year	US week	ISO date
Monday	March 23, 2026	82 of 365	13	2026-W13-1
Tuesday	March 24, 2026	83 of 365	13	2026-W13-2
Wednesday	March 25, 2026	84 of 365	13	2026-W13-3
Thursday	March 26, 2026	85 of 365	13	2026-W13-4
Friday	March 27, 2026	86 of 365	13	2026-W13-5
Saturday	March 28, 2026	87 of 365	13	2026-W13-6
Sunday	March 29, 2026	88 of 365	14	2026-W13-7

Week 13 at a glance

ISO code: 2026-W13 (Monday is 2026-W13-1, Sunday is 2026-W13-7)
Month: March
Quarter: Q1 of 2026
Day of year: Days 82–88 of 365
US week number: Monday–Saturday: US week 13; Sunday: US week 14 (Sunday-start weeks, week 1 contains January 1)
Even or odd: Week 13 is an odd week
Weeks left: After this week, 40 ISO weeks remain in 2026 (53 weeks in total)
Year progress: By Sunday, 24% of 2026 has passed

Holidays and key dates

Sunday, March 29: Summer time starts in the EU and UK (clocks go forward one hour)

Week numbers follow ISO 8601: weeks start on Monday and week 1 contains the first Thursday of the year. US weeks start on Sunday, with week 1 containing January 1.

Questions about week 13, 2026

What are the dates of week 13 in 2026?

Week 13 of 2026 starts on Monday, March 23, 2026 and ends on Sunday, March 29, 2026.

What month is week 13 of 2026?

Week 13 falls in March. By the Thursday rule that ISO 8601 uses for years and quarters, it counts as a March week.

How do I get week 13 of 2026 in Excel or Google Sheets?

=ISOWEEKNUM(DATE(2026,3,23)) returns 13. To go the other way, =DATE(2026,1,4)-WEEKDAY(DATE(2026,1,4),2)+1+(13-1)*7 returns the Monday, March 23, 2026.