Skip to content
DateAlmanac

September 2031

  • 30 days
  • Starts Monday
  • Ends Tuesday
  • 21 working days
  • 8 weekend days
  • ISO weeks 36–40
Calendar grid for 9/2031, weeks starting Sun
ISO week number, Monday to Sunday
36
37
38
39
40

Holiday or observanceWeekend

Holidays in September

  • Labor DaySep 1
  • National Grandparents DaySep 7
  • Patriot DaySep 11

Federal holidays from 5 U.S.C. §6103, plus widely kept US observances. 3 religious dates fall in September 2031 as well — see the calendar with every holiday.

Moon phases

  • Full moon

    Mon, Sep 1

    5:20 AM ET

  • Last quarter

    Mon, Sep 8

    12:14 PM ET

  • New moon

    Tue, Sep 16

    2:46 PM ET

  • First quarter

    Tue, Sep 23

    9:19 PM ET

  • Full moon

    Tue, Sep 30

    2:57 PM ET

Times in US Eastern. Computed from Meeus, Astronomical Algorithms, ch. 49.

The moon through September

  1. 1
  2. 3
  3. 5
  4. 7
  5. 9
  6. 11
  7. 13
  8. 15
  9. 17
  10. 19
  11. 21
  12. 23
  13. 25
  14. 27
  15. 29
  16. 30
The moon every other evening, drawn at its true illumination. The terminator is a semi-ellipse, not a straight edge — it only looks straight at the quarters.

About September 2031

September 2031 has 30 days. It begins on a Monday and ends on a Tuesday, which gives the month five Mondays and Tuesdays — and only four of every other weekday. Of its 22 weekdays, 1 is a federal holiday, leaving 21 working days.

The September equinox falls on Tuesday, September 23, 2031, the 23rd of the month.

2031 at a glance

Calendar with holidaysPrintable versionDownload PDFFull year 2031