What day is the first day of spring 2025? This week sees the vernal (meaning “spring”) equinox, which marks the beginning of astronomical spring in the Northern Hemisphere and astronomical fall (or autumn) in the Southern Hemisphere.
Equinoxes happen twice a year, as do solstices. Here’s everything you need to know about when they are and what they mean.
When Is The Spring Equinox In 2025?
This year’s spring equinox will occur on Thursday, March 20, at precisely 09:01 UTC. That translates to these times in North America:
• 3:01 a.m. EDT
• 2:01 a.m. CDT
• 1:01 a.m. MDT
• 12:01 a.m. PDT
• 11:01 p.m. AKDT (Alaska)
• 9:01 p.m. HST (Hawaii)
According to Timeanddate.com, the March equinox always occurs between March 19 and 21, while the September equinox happens between September 21 and 24.
What Is The Spring Equinox?
“Equinox” is Latin, with equi meaning “equal” and nox meaning “night.” The March equinox is one of two days each year when every location on the planet experiences equal amounts of sunlight, so 12 hours of day and 12 hours of night. It marks the moment when the sun is directly above the equator at midday.
That’s not always the case because Earth orbits the sun on an axis tilted by 23.4 degrees. A consequence of that tilt is each hemisphere receiving different amounts of sunlight throughout the year — causing the seasons.
March’s equinox is called the spring equinox in the Northern Hemisphere because it signals the point in Earth’s orbit when this region of the planet begins getting more hours of sunlight than darkness, so begins to warm up. In the Southern Hemisphere, the March equinox has the opposite effect, as the region begins to tilt away from the sun, marking the end of summer and the start of fall (or autumn).
What Are The Solstices?
While equinoxes mark the moments when the sun crosses the celestial equator, solstices indicate the days when Earth’s axis is tilted toward or away from the sun. This creates the longest period of daylight in one hemisphere and the longest night in the other.
The next solstice — called the summer solstice in the Northern Hemisphere because it signals the beginning of summer — will occur on Friday, June 20. It will be followed by the September (fall) equinox on Monday, Sept. 22, and the December (winter) solstice on Sunday, Dec. 21.
Why The Northern Lights Are More Common At Equinox
The same celestial geometry that ensures equal day and night on Earth also positions the planet’s axis side-on to the sun. According to the Russell-McPherron Effect, this causes an alignment of Earth’s magnetic field with that of the solar wind — charged particles from the sun‚ temporally making displays of aurora more frequent and more intense.
Solar activity is also at a 23-year high, with the sun thought to have reached solar maximum — the peak of the 11-year Solar Cycle — last October.
How To See The Spring Equinox
The equinox itself is not a visible astronomical event — except for the sun appearing higher in the sky at midday in the Northern Hemisphere. It’s best appreciated at sunrise or sunset on the day itself because only on the day of an equinox does the sun rise due east and set due west. The fastest sunsets and sunrises of the year occur on the equinoxes, according to EarthSky.
Another sure-fire way of seeing the arrival of spring written in the stars is to look north from the Northern Hemisphere after dark to see the Big Dipper riding high. Stargazers even have a memory aid in honor of the sight — “spring up, fall down.”
Wishing you clear skies and wide eyes.
