Days until September 15
September 15 falls on a Tuesday in 2026 and a Wednesday in 2027. The count runs from today’s date on your device to the next September 15; pick another date to count from it instead.
- Days until September 15
- 350
From September 30, 2026, there are 350 days until September 15 on Wednesday, September 15, 2027.
- Date
- Wednesday, September 15, 2027
- Day of the week
- Wednesday
- In weeks
- 50 weeks
Answer for the example date Wednesday, September 30, 2026. It changes to today's date when the page loads.
Days until September 15: 350. From September 30, 2026, there are 350 days until September 15 on Wednesday, September 15, 2027.
Where is September 15 on the calendar?
How to calculate
Counts the days from today, or any date you choose, to the next September 15, with its day of the week.
Example with the default inputs (Count from September 30, 2026) on the example date Wednesday, September 30, 2026: From September 30, 2026, there are 350 days until September 15 on Wednesday, September 15, 2027.
Method: Find the first September 15 on or after the start date, then count the days from the start date to it.
- September 15 comes every year, so the count is never more than 365 days.
- The start date itself is not counted: from the day before September 15, the count is 1; on September 15 itself, it is 0.
- Start dates from January 1, 1900 to December 31, 2400 work for the count to September 15, the range the date field accepts.
- Today is the date on your own device, so the count to September 15 changes at midnight where you are. Dates are whole calendar days, so a daylight-saving change never adds or loses a day.
Worked examples
Each example is checked against the calculator on every build.
- Count from 2027-09-15 gives Date 2027-09-15, Days until September 15 0.Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years)
- Count from 2027-01-01 gives Date 2027-09-15, Days until September 15 257.Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years)
- Count from 2027-09-16 gives Date 2028-09-15, Days until September 15 365.Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years)
Other questions people ask
What day of the week is September 15?
Tuesday, September 15, 2026; Wednesday, September 15, 2027; Friday, September 15, 2028. The weekday of September 15 moves on one day a year, or two when a February 29 falls between.
What day of the year is September 15?
September 15 is day 258 of a common year and day 259 of a leap year, such as 2028. Either way, 107 days of the year come after it.
What season is September 15 in?
In the Northern Hemisphere, September 15 is in summer in every year from 2026 to 2035; in the Southern Hemisphere, it is winter. Seasons here start on the astronomical equinoxes and solstices, dated in US Eastern Time.
Is September 15 a US federal holiday?
No. No US federal holiday falls on September 15. The next one in the calendar after September 15 is Columbus Day, which falls between October 8 and October 14.
How are the days until September 15 counted?
From the start date to September 15, without counting the start date: from September 14 the count is 1, and on September 15 it is 0. The day after, it moves on to the next September 15: from September 16, 2026, that is September 15, 2027, 364 days away.