Days until fall
The first day of fall 2027 is on Thursday, September 23, 2027. The count starts from today’s date; pick another date to count from it instead.
- Days until Fall
- 359
From September 29, 2026, there are 359 days until the first day of fall on Thursday, September 23, 2027.
- Date
- Thursday, September 23, 2027
- Day of the week
- Thursday
- In weeks
- 51 weeks and 2 days
Answer for the example date Tuesday, September 29, 2026. It changes to today's date when the page loads.
Days until Fall: 359. From September 29, 2026, there are 359 days until the first day of fall on Thursday, September 23, 2027.
Where is the first day of fall on the calendar?
How to calculate
Counts the days from today, or any date you choose, to the next first day of fall, with its date and day of the week.
Example with the default inputs (Count from September 29, 2026) on the example date Tuesday, September 29, 2026: From September 29, 2026, there are 359 days until the first day of fall on Thursday, September 23, 2027.
Method: Find the first date of the first day of fall on or after the start date, then count the days from the start date to it.
- Fall (autumn) starts at the September equinox (September 22 or 23 in US Eastern Time), when the Sun crosses the equator going south.
- Start dates from January 1, 2007 to December 31, 2060 work, because the dates are checked against the US Naval Observatory for these years, and US daylight time has started in March since 2007.
- The start date itself is not counted: from the day before, the count is 1; on the day itself, it is 0.
- Dates are calendar days with no time of day, so a time zone or a daylight-saving change never adds or loses a day.
Worked examples
Each example is checked against the calculator on every build.
- Count from 2026-01-01 gives Date 2026-09-22, Days until Fall 264.Source: US Naval Observatory seasons API (https://aa.usno.navy.mil/api/seasons), converted to US Eastern Time; Meeus, Astronomical Algorithms, ch. 27
- Count from 2026-09-23 gives Date 2027-09-23, Days until Fall 365.Source: US Naval Observatory seasons API (https://aa.usno.navy.mil/api/seasons), converted to US Eastern Time; Meeus, Astronomical Algorithms, ch. 27
Other questions people ask
When is the first day of fall 2027?
The first day of fall 2027 is on Thursday, September 23, 2027.
When is the first day of fall 2028?
The first day of fall 2028 is on Friday, September 22, 2028.
How is the date of the first day of fall set?
Fall (autumn) starts at the September equinox (September 22 or 23 in US Eastern Time), when the Sun crosses the equator going south. Source: US Naval Observatory seasons API (https://aa.usno.navy.mil/api/seasons), converted to US Eastern Time.
How are the days until the first day of fall counted?
From the start date (today, unless you change it) to the date, without counting the start date. The day before, the count is 1; on the day itself, it is 0; the day after, the count moves on to the next first day of fall.