The spring equinox will occur at 5:01 a.m. EDT on Thursday. Here's what to know about the start of the spring season.

Equinoxes mark the only time of the year when both the north and south poles are lit by the Sun at the same time. The spring equinox happens when the Sun appears directly over the equator, with all parts of the globe seeing nearly equal days and nights.

Spring equinox means the first official day of spring is here. Discover the science and traditions of what’s also called the vernal equinox..