Old Farmer’s Almanac
When Is the First Day of Spring 2023?
In 2023, the March equinox happens on March 20, at 4:24 p.m. CDT. This falls on a Monday and is the astronomical beginning of the spring season in the Northern Hemisphere and the autumn season in the Southern Hemisphere.
If you thought that the spring equinox only ever occurred on March 21, you may be dating yourself. The civil calendar date of the equinox continues to shift every year.
What Is the Spring Equinox?
In the Northern Hemisphere, the spring equinox in the Northern Hemisphere (also called the March equinox or vernal equinox across the globe) occurs when the Sun crosses the celestial equator going south to north.
It’s called the “celestial” equator because it’s an imaginary line in the sky above the Earth’s equator. Imagine standing on the equator; the Sun would pass directly overhead on its way north.
On the March equinox, the Northern Hemisphere and Southern Hemisphere receive roughly equal amounts of sunlight; neither hemisphere is tilted more toward or away from the Sun than the other.
Although in most locations (the North Pole and Equator being exceptions) the amount of daylight had been increasing each day after the winter solstice, after the spring equinox, many places will experience more daylight than darkness in each 24-hour day. The amount of daylight each day will continue to increase until the summer solstice in June, during which the longest period of daylight occurs.
Here’s an interesting fact: Equinoxes are the only two times each year that the Sun rises due east and sets due west for all of us on Earth.
While the Sun passes overhead, the tilt of the Earth is zero relative to the Sun, which means Earth’s axis neither points toward nor away from the Sun. (Note, however, the Earth never orbits upright, but is always tilted on its axis by about 23.5 degrees.)
What Does “Equinox” Mean?
The word equinox comes from the Latin words for “equal night” — aequus (equal) and nox (night). On the equinox, the length of day and night is nearly equal in all parts of the world.