# Days until September 23

Counts the days from today, or any date you choose, to the next September 23, with its day of the week.

- Page: https://www.acalculator.org/days/days-until-september-23
- JSON spec: https://www.acalculator.org/days/days-until-september-23.json
- Version: 04d19d66ceb3

## Default answer

Example with the default inputs (Count from September 30, 2026) on the example date Wednesday, September 30, 2026: From September 30, 2026, there are 358 days until September 23 on Thursday, September 23, 2027.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| from | Count from | The date to count from. Today, unless you change it. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| days | Days until September 23 | Whole days from the start date to the next September 23; 0 on the day itself. |
| date | Date | The next September 23 on or after the start date. |
| weekday | Day of the week | The weekday of that date. |
| weeks | In weeks | The same number of days in weeks and days. |

## Method

Find the first September 23 on or after the start date, then count the days from the start date to it.

## Assumptions

- September 23 comes every year, so the count is never more than 365 days.
- The start date itself is not counted: from the day before September 23, the count is 1; on September 23 itself, it is 0.
- Start dates from January 1, 1900 to December 31, 2400 work for the count to September 23, the range the date field accepts.
- Today is the date on your own device, so the count to September 23 changes at midnight where you are. Dates are whole calendar days, so a daylight-saving change never adds or loses a day.

## Worked examples

1. from = 2027-09-23 gives date = 2027-09-23, days = 0. Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years).
2. from = 2027-01-01 gives date = 2027-09-23, days = 265. Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years).
3. from = 2027-09-24 gives date = 2028-09-23, days = 365. Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years).

## FAQ

### What day of the week is September 23?

Wednesday, September 23, 2026; Thursday, September 23, 2027; Saturday, September 23, 2028. The weekday of September 23 moves on one day a year, or two when a February 29 falls between.

### What day of the year is September 23?

September 23 is day 266 of a common year and day 267 of a leap year, such as 2028. Either way, 99 days of the year come after it.

### What season is September 23 in?

In the Northern Hemisphere, September 23 is in fall in 2026, 2028, 2029, 2030, 2032, 2033, and 2034 and the first day of fall (the September equinox) in 2027, 2031, and 2035, because the equinox or solstice moves by a day between years. Seasons here start on the astronomical equinoxes and solstices, dated in US Eastern Time.

### Is September 23 a US federal holiday?

No. No US federal holiday falls on September 23. The next one in the calendar after September 23 is Columbus Day, which falls between October 8 and October 14.

### How are the days until September 23 counted?

From the start date to September 23, without counting the start date: from September 22 the count is 1, and on September 23 it is 0. The day after, it moves on to the next September 23: from September 24, 2026, that is September 23, 2027, 364 days away.

## Sources

- 5 U.S.C. 6103 (federal holidays; weekend rule in 6103(b) and Executive Order 11582). Checked against OPM holiday schedules.
- Equinoxes and solstices: Jean Meeus, Astronomical Algorithms (2nd ed., 1998), chapter 27, checked against the US Naval Observatory.