Govind Tekale
The vernal equinox marks the official start of spring in the Northern Hemisphere, bringing longer days and warmer weather. This year, it occurs on Thursday, March 20, 2025, at precisely 5:01 a.m. EDT (2:01 a.m. PDT).
The Science Behind the Equinox
The word “equinox” comes from Latin, meaning “equal night.” During this astronomical event, the Earth’s axis isn’t tilted toward or away from the Sun. This creates nearly equal periods of daylight and darkness across the globe.
“Nearly” is the key word here. Despite its name, most places won’t experience exactly 12 hours of day and night on the equinox. For example, Sacramento will see 12 hours and 10 minutes of daylight on March 20, according to meteorologist Heather Waldman.
There are several reasons for this slight imbalance:
- Geographic location: The farther north you are from the equator, the longer your daylight hours during the spring equinox. Fairbanks, Alaska will experience 12 hours and 17 minutes of daylight.
- The sun’s appearance: The sun isn’t just a point of light but a disc. Officially, sunrise occurs when the top edge first appears over the horizon, while sunset isn’t complete until the top edge disappears below it.
- Atmospheric refraction: Earth’s atmosphere bends sunlight, making sunrise appear slightly earlier and sunset slightly later than they actually occur.
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Cultural Significance
The spring equinox holds deep cultural significance worldwide:
Ancient civilizations built monuments aligned with the equinox. At Chichen Itza in Mexico, the pyramid of El Castillo creates a shadow pattern resembling a serpent descending the stairs during the equinox.
Many cultures celebrate this time as a period of renewal:
- Nowruz, the Iranian New Year, coincides with the spring equinox
- In Japan, Shunbun no Hi is a public holiday for family reunions
- The Hindu festival of Holi often falls near this time
- Modern pagans observe Ostara, celebrating fertility and balance
Seasonal Changes
The Northern Hemisphere will now experience:
- Gradually increasing temperatures
- Longer daylight hours
- Blooming flowers and plants
- Animals becoming more active
Meanwhile, in the Southern Hemisphere, the March equinox marks the beginning of autumn, with days growing shorter and temperatures cooling.
What’s Next?
After the spring equinox, the Northern Hemisphere will continue tilting toward the sun until the summer solstice on June 20, 2025, at 10:41 p.m. EDT—the longest day of the year.
It’s worth noting that meteorologists actually define spring differently. The meteorological spring, based on temperature patterns rather than astronomical events, began on March 1.
FAQ
What is the exact time of the 2025 spring equinox? +
The spring equinox will occur at 5:01 a.m. EDT (2:01 a.m. PDT) on Thursday, March 20, 2025, according to the National Weather Service.
Why isn’t day and night exactly equal on the equinox? +
Despite the name meaning “equal night,” most locations don’t experience exactly 12 hours of daylight and darkness. This is due to three main factors: your latitude (distance from the equator), the fact that the sun appears as a disc rather than a point, and atmospheric refraction that bends sunlight.
What’s the difference between the spring equinox and summer solstice? +
The spring equinox occurs when the Earth’s axis is neither tilted toward nor away from the sun, creating nearly equal day and night. The summer solstice happens when the Northern Hemisphere is at its maximum tilt toward the sun, creating the longest day and shortest night of the year.
How do different cultures celebrate the spring equinox? +
Many cultures have celebrations tied to the spring equinox, including Nowruz (Iranian New Year), Shunbun no Hi in Japan, Holi in India, and Ostara among modern pagan communities. These celebrations often focus on themes of renewal, balance, and new beginnings.
What’s the difference between astronomical and meteorological spring? +
Astronomical spring begins with the vernal equinox (March 20 in 2025) and is based on the Earth’s position relative to the sun. Meteorological spring, used by weather forecasters, begins on March 1 and is based on annual temperature cycles and calendar months.
Will the spring equinox happen on the same date every year? +
No, the spring equinox can fall between March 19-21, depending on the year. This variation occurs due to the Earth’s orbit around the sun and our calendar system, including leap years which help keep seasonal events aligned with our calendar.
