Did you know this is the earliest spring since 1896?
According to the EarthSky News, the March equinox, when the sun crosses the celestial equator going from south to north, signals the beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. The March equinox can actually come on March 19, 20 or 21. This year has the earliest March equinox since the year 1896. This earliest spring is happening because the tropical year, as measured between successive March equinoxes, doesn’t have an even number of days (365.242 days). Our calendar, on the other hand, has an even 365 days in a common year and 366 days in a leap year. The centennial year 2000 was a leap year, which causes the March equinox to arrive roughly three-quarters of a day earlier in the 21st century (2001-2100) than at corresponding years in the 20th century (1901-2000). So four years from now, in 2020, the March equinox will be earlier yet – on March 20 at 3:50 universal time (March 19 at 10:50 p.m. Central Daylight Time).
Incidentally, the centennial year 2100 will not be a leap year because in 1582, Pope Gregory XIII revised the Julian calendar and stated that leap days should not be added in years ending in “00” unless that year is also evenly divisible by 400. This means in 2100 the March equinox times will be pushed upward again (by roughly one-quarter day) in the 22nd century (2101-2200).
The complete explanation is at the EarthSky website at http://earthsky.org/astronomy-essentials/everything-you-need-to-know-vernal-or-spring-equinox?utm_source=EarthSky+News&utm_campaign=7329c5f21c-EarthSky_News&utm_medium=email&utm_term=0_c643945d79-7329c5f21c-394611693