Thursday March 20th 2025 at 5:01am was the spring equinox. Spring equinox is when the sun crosses the celestial equator and marks the start of spring in the northern hemisphere and the start of autumn in the southern hemisphere, with day and night nearly equal in length. Spring equinox lasts for 1 day. It occurs when the Earth’s axis tilts at 23.5 degrees which causes the seasons. The word equinox means the time or date (twice each year) at which the sun crosses the celestial equator when day and night are approximately the same length.