The March equinox – also called the vernal equinox – is the beginning of the spring season in the Northern Hemisphere and autumn season in the Southern Hemisphere. It arrives on March 20, 2021, at 09:37 UTC (Coordinated Universal Time) or 4:37 a.m. CDT (Central Daylight Time).
During this equinox, the Sun will shine directly on the equator with nearly equal amounts of day and night, about 12 hours. Throughout the world, the Northern and Southern hemispheres will get equal amounts of daylight.
The equinoxes and solstices are caused by Earth’s tilt on its axis and ceaseless motion in orbit. Think of an equinox as happening on the imaginary dome of our sky, or as an event that happens in Earth’s orbit around the Sun.
In the Northern Hemisphere, the March equinox will bring us earlier sunrises, later sunsets, softer winds, and budding plants. With the opposite season, south of the equator, there will be later sunrises, earlier sunsets, chillier winds, and dry, falling leaves.
If you’re in the Northern Hemisphere, start watching the Sun as it sets just a bit farther north on the horizon each evening until the summer solstice. Also, enjoy the warmer weather and extended daylight!
Happy equinox, Earthlings! March 20 marks the spring equinox, one of two seasonal markers in Earth’s year-long orbit when the Sun appears to shine directly over the equator, and daytime and nighttime are nearly equal lengths–12 hours–everywhere on the planet.
It’s the start of astronomical spring in the Northern Hemisphere, meaning more sunlight and longer days. From here until the beginning of fall, daytime will be longer than nighttime as the Sun travels a longer, higher arc across the sky each day, reaching a peak at the start of summer. It’s just the opposite in the Southern Hemisphere, where March 20 marks the fall equinox.
What’s more? The first full Moon of spring will rise tonight, lighting the skies on the equinox. Usually, a full Moon arrives a few days to weeks before or after the equinox. It’s close, but not a perfect match. Tonight’s full Moon, however, reaches maximum illumination less than four hours after the equinox. There hasn’t been a comparable coincidence since the spring equinox in 2000.
And because the Moon is near perigee, it qualifies as a supermoon–the third and final of 2019. It’s not a big supermoon, so you won’t really be able to see the difference between this full Moon and any other one with your eyes. But keep an keep an eye on the Moon as it rises and creeps above the eastern skyline. A low-hanging Moon can appear strangely inflated. This is the Moon illusion at work.
Super or seemingly not, it’s a rare celestial coincidence to usher in springtime.