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September 2025 calendar

30 days22 weekdaysStarts on MondayISO weeks 36–40

September 2025
WkMonTueWedThuFriSatSun
36
37
38
39
40

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September 2025 in numbers

Days
30
Weekdays (Mon–Fri)
22
Weekend days
8
First and last day
Monday – Tuesday
First and last working day
Mon, Sep 1 – Tue, Sep 30
Week numbers
36–40
Day of the year
244–273
Quarter
Q3 2025
Islamic months (computed)
Rabi' al-Awwal – Rabi' al-Thani 1447 AH

With 30 days, September 2025 has four full weeks plus 2 extra days, so Monday and Tuesday occur five times; every other weekday occurs four times. It has 8 weekend days and 22 weekdays.

September 1 is day 244 of the year, so September 2025 covers day numbers 244 to 273. In the Umm al-Qura Islamic calendar, 1 Rabi' al-Thani 1447 AH falls on September 23 (computed; where months begin with the sighting of the new crescent, the start can differ by a day).

Public holidays in September 2025

Computed from each holiday’s legal rule; holidays set by announcement are left out for 2025.

DateHolidayWhere
Mon, Sep 1Labor DayUnited States (federal)
Mon, Sep 1Labour DayCanada (federal)
Mon, Sep 15Respect for the Aged DayJapan
Wed, Sep 24Heritage DaySouth Africa
Tue, Sep 30National Day for Truth and ReconciliationCanada (federal)

National holidays of the 17 sets we take from official government sources; see public holidays by country for regional days and sources. Where a holiday that falls on a weekend moves to a weekday, the table shows the day off.

Other dates in September 2025

Days that many people keep but that are not public holidays in our 17 sets, each from its fixed rule. Jewish dates begin at sunset the evening before; Islamic dates follow the Umm al-Qura calendar and are announced locally.

Clock changes and seasons

Clock changes from IANA tzdata as the rules stand today. Equinox and solstice times are the US Naval Observatory’s, in UTC.

Questions

How many weekdays are in September 2025?
22 weekdays (Monday to Friday) and 8 weekend days, out of 30 days. Public holidays are not subtracted, because they depend on the country; this month has 5 holiday dates in the countries we cover (see the table on this page).
What day does September 2025 start on?
September 2025 starts on Monday, September 1, 2025 and ends on Tuesday, September 30, 2025. The first working day is Mon, Sep 1 and the last is Tue, Sep 30.
What week numbers are in September 2025?
Under ISO 8601 (weeks from Monday) September 2025 spans weeks 36–40. The week number page explains the rule.
What is the day number of September 1, 2025?
September 1 is day 244 of 2025 and September 30 is day 273. In the YYDDD format often called a Julian date, the month runs from 25244 to 25273.
What holidays are in September 2025?
Labor Day (Mon, Sep 1: United States (federal)); Labour Day (Mon, Sep 1: Canada (federal)); Respect for the Aged Day (Mon, Sep 15: Japan); Heritage Day (Wed, Sep 24: South Africa); National Day for Truth and Reconciliation (Tue, Sep 30: Canada (federal)).

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