# Days until March 21

Counts the days from today, or any date you choose, to the next March 21, with its day of the week.

- Page: https://www.acalculator.org/days/days-until-march-21
- JSON spec: https://www.acalculator.org/days/days-until-march-21.json
- Version: dc7903a7f214

## 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 172 days until March 21 on Sunday, March 21, 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 March 21 | Whole days from the start date to the next March 21; 0 on the day itself. |
| date | Date | The next March 21 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 March 21 on or after the start date, then count the days from the start date to it.

## Assumptions

- March 21 comes every year, so the count is never more than 365 days.
- The start date itself is not counted: from the day before March 21, the count is 1; on March 21 itself, it is 0.
- Start dates from January 1, 1900 to December 31, 2400 work for the count to March 21, the range the date field accepts.
- Today is the date on your own device, so the count to March 21 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 = 2027-03-21 gives date = 2027-03-21, 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 = 2027-03-21, days = 79. Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years).
3. from = 2027-03-22 gives date = 2028-03-21, 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 March 21?

Saturday, March 21, 2026; Sunday, March 21, 2027; Tuesday, March 21, 2028. The weekday of March 21 moves on one day a year, or two when a February 29 falls between.

### What day of the year is March 21?

March 21 is day 80 of a common year and day 81 of a leap year, such as 2028. Either way, 285 days of the year come after it.

### What season is March 21 in?

In the Northern Hemisphere, March 21 is in spring in every year from 2026 to 2035; in the Southern Hemisphere, it is autumn. Seasons here start on the astronomical equinoxes and solstices, dated in US Eastern Time.

### Is March 21 a US federal holiday?

No. No US federal holiday falls on March 21. The next one in the calendar after March 21 is Memorial Day, which falls between May 25 and May 31.

### How are the days until March 21 counted?

From the start date to March 21, without counting the start date: from March 20 the count is 1, and on March 21 it is 0. The day after, it moves on to the next March 21: from March 22, 2026, that is March 21, 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.