Week 13 of 2026 runs March 23 to March 29

ISO week 13 of 2026 begins on Monday, March 23, 2026 and ends on Sunday, March 29, 2026. It has already passed; the current week is 39. The week covers March only.

What dates are in week 13?

No holiday or widely marked observance falls inside week 13 of 2026. The seven dates always run Monday through Sunday, which is the part of ISO 8601 that most often catches people out: a week that starts on Sunday is a different convention and gives a different number.

How ISO week 13 is worked out

ISO 8601 fixes week one as the week containing the first Thursday of January, which is the same as saying the week containing 4 January, or the week holding the majority of its days in the new year. Counting forward from there, week 13 is the 13th Monday-to-Sunday block of 2026, which lands on March 23. All seven dates sit inside 2026, so the ISO year and the calendar year agree for this week.

When is week 13 in other years?

Week 13 shifts by a day or two each year because a year is 52 weeks plus one or two days, so the Monday that opens it moves from March 23 in 2026 to March 29 in 2027.

How far away is week 13?

Today is Wednesday, September 23, 2026, which sits in ISO week 39 of 2026. Week 13 of 2026 closed 178 days ago. The same week number in the following year is listed in the table above.

Questions

What dates are in week 13 of 2026?

Monday March 23, 2026 through Sunday March 29, 2026.

What week is it now?

ISO week 39 of 2026. Today is Wednesday, September 23, 2026.

How many weeks does 2026 have?

53. The 2026 week count page explains the rule.

Do ISO weeks start on Monday or Sunday?

Monday. A Sunday-first week is a different convention and can give a different week number for the same date.

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