Spring equinox: Here's what you should know about the first day of spring
CBS News - 03-20
By the end of the day, spring will officially have sprung — even if it doesn't feel like yet it in your city. March 20, 2019, marks the spring equinox — the first official day of spring in the Northern Hemisphere. This day is unique in that the length of day and night are close to equal, NASA explains.