When Is Spring Equinox 2025. Spring 2025 starts on thursday, march 20th in the northern hemisphere, with daylight time lengthening and the leaves begining show on the trees with the changing tilt of the earth's. Spring equinox 2025 (beginning of astronomical spring) on the day of the spring (march) equinox, the sun crosses the celestial equator, moving along the ecliptic.
In 2025, the official first day of spring is thursday, march 20. This date marks the spring equinox in the northern hemisphere.