Week 37 of 2026 runs September 7 to September 13

ISO week 37 of 2026 begins on Monday, September 7, 2026 and ends on Sunday, September 13, 2026. It has already passed; the current week is 39. The week covers September only.

What dates are in week 37?

Week 37 of 2026 contains Labor Day on September 7 and Patriot Day on September 11. 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 37 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 37 is the 37th Monday-to-Sunday block of 2026, which lands on September 7. All seven dates sit inside 2026, so the ISO year and the calendar year agree for this week.

When is week 37 in other years?

Week 37 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 September 7 in 2026 to September 13 in 2027.

How far away is week 37?

Today is Wednesday, September 23, 2026, which sits in ISO week 39 of 2026. Week 37 of 2026 closed 10 days ago. The same week number in the following year is listed in the table above.

Questions

What dates are in week 37 of 2026?

Monday September 7, 2026 through Sunday September 13, 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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