The March equinox marks the official start of spring in the Northern Hemisphere and autumn in the Southern Hemisphere, with the sun positioned directly over the Earth’s equator. The phenomenon occurred on March 20, 2025, at 09:01 UTC (06:01 Brasília time), after a harsh winter in several regions of the northern hemisphere. From that date onwards, the days begin to get progressively longer in the northern hemisphere, while in the southern hemisphere the nights become longer. The astronomical event balances the lighting between the two hemispheres, resulting in periods of light and darkness approaching 12 hours each.
The term equinox derives from Latin and means “equal night”, highlighting the approximate equality between day and night. The axial inclination of Terra of 23.4 degrees in relation to the orbital plane causes seasonal variations throughout the year. At the time of the equinox, the planetary axis aligns so that the sun falls perpendicularly on the equatorial line, promoting this balanced distribution of sunlight.
The equinox differs from the meteorological beginning of spring, which occurs on March 1 in the northern hemisphere and is based on three-month climate cycles. The 2024-2025 meteorological winter recorded above-average temperatures on a global scale, despite episodes of intense cold in areas such as the northeast of Estados Unidos and parts of Europa. The astronomical equinox signals the gradual transition to milder conditions in the Northern Hemisphere.
What happens at the March equinox
The sun crosses the celestial equator from south to north, changing its apparent position in the sky. Essa gradual change increases the daily duration of sunlight in the Northern Hemisphere. Regiões at mid-latitudes see gains of minutes per day in lighting.
The phenomenon occurs simultaneously across the planet, regardless of the local time zone. Observadores at the equator see the sun directly overhead at noon. The transition affects the angle of incidence of solar rays, influencing temperatures over the following weeks.
Differences between astronomical and meteorological spring
Astronomical spring begins with the March equinox in the northern hemisphere. Já The weather begins on March 1st and divides the year into fixed periods of three months to facilitate climate analysis.
This distinction allows for consistent comparisons of historical data. The 2024-2025 meteorological winter showed positive temperature anomalies across much of the globe, with above-normal heat records across oceans and continents.
Impact on daylight cycles
After the equinox, the northern hemisphere receives more hours of sunlight each day. The process continues until the June solstice, when the longest day of the year occurs.
In the Southern Hemisphere, astronomical autumn brings longer nights. The axial tilt of Terra determines this seasonal variation by modifying solar exposure at each pole.
Astronomical explanation of the phenomenon
Terra orbits the sun in an ecliptic plane while maintaining its tilted axis. At the March equinox, the subsolar point is positioned exactly over the equator.
This alignment results in equal solar incidence in both hemispheres. From there, the apparent movement of the sun shifts to higher latitudes in the north.
Traditional celebrations and observations
Several cultures mark the equinox with rituals of renewal and balance. Festivais celebrate the return of fertility to the land in the northern hemisphere.
Astronomical observations include tracking sunrises and sunsets aligned with local landmarks. The event reinforces the understanding of Earth’s orbital movement.
Transition to next stations
The next seasonal milestone is the June solstice, which marks the beginning of summer in the Northern Hemisphere. Autumn arrives with the September equinox.
These cycles repeat annually due to the elliptical orbit and axial tilt. The March equinox lays the foundation for the progressive increase in heat in the north.
