March Equinox - Equal Day and Night, Nearly
March Equinox in Washington DC, District of Columbia, USA is on
Saturday, March 20, 2021 at 5:37 am EDT (Change city)
- Sunrise, sunset and day length around March Equinox 2021
- Countdown to March Equinox 2021 in Washington DC, District of Columbia, USA
March Equinox in Universal Coordinated Time is on
Saturday, March 20, 2021 at 09:37 UTC
- Local times for March Equinox 2021 worldwide
- Day and Night map for March Equinox 2021
- Equinoxes and solstices from 2000–2049
The Sun Crosses the Equator
The March equinox marks the moment the Sun crosses the celestial equator, the imaginary line in the sky above the Earth's equator, from south to north. This happens on March 19, 20, or 21 every year.
2020's March Equinox fell on March 19 in all time zones in the United States, making it the earliest spring equinox in the country since 1896.
Northern Spring, Southern Fall
Equinoxes and solstices are opposite on either side of the equator. The March equinox is the spring (vernal) equinox in the Northern Hemisphere, marking the start of astronomical spring. In the Southern Hemisphere, it is the autumnal (fall) equinox, which marks the beginning of fall.
On the equinox, night and day are nearly the same length, 12 hours, all over the world. This is the reason it's called an “equinox,” derived from Latin, meaning “equal night.” However, in reality, equinoxes don't have exactly 12 hours of daylight.
What Happens on the Equinox?
Earth's axis is tilted at an angle of about 23.4° in relation to the ecliptic plane, the imaginary plane created by the Earth's path around the Sun. On any other day of the year, either the Southern Hemisphere or the Northern Hemisphere tilts a little towards the Sun. But on the two equinoxes, the tilt of the Earth's axis is perpendicular to the Sun's rays, like the illustration shows.
Start of the Tropical Year
The March equinox is often used by astronomers to measure a tropical year, the mean time it takes for the Earth to complete a single orbit around the Sun. Also known as a solar year, a tropical year is approximately 365 days, 5 hours, 48 minutes, and 45 seconds long.
The time between one March equinox and the next can vary by only a few minutes or by as many as 30 minutes each year.
|March 2019 – March 2020||365||5||51||4|
|March 2020 – March 2021||365||5||47||55|
|March 2021 – March 2022||365||5||55||54|
|March 2022 – March 2023||365||5||50||55|
|March 2023 – March 2024||365||5||42||8|
Celebrating New Beginnings
The Snake of Sunlight
One of the most famous ancient Spring equinox celebrations was the Mayan sacrificial ritual by the main pyramid at Chichen Itza, Mexico.
The main pyramid, also known as El Castillo, has four staircases running from the top to the bottom of the pyramid's faces.
The staircases are built at a carefully calculated angle, which makes it look like an enormous snake of sunlight slithers down the stairs on the day of the equinox. The pyramid is notorious for the bloody human sacrifices that used to take place here.
Knowledge of the equinoxes and solstices is also crucial in developing dependable calendars, another thing the Mayans clearly had got the hang of.