Earliest Spring in All of Our Lifetimes!

The website, Space.com (a favorite of mine) explains what this is such an early event:

First, that 2020 is a leap year (meaning that the month of February had one extra day) is not the reason for the early arrival of this year's equinox. Rather, it is the leap year that we observed in the year 2000.
Let's look at the dates and times of the vernal equinoxes leading up to 2000. Note that each year the occurrence of the equinox happens about 6 hours (or one-quarter of a day) later in the calendar:

• 1996: March 20 at 3:03 a.m. EST (0803 GMT)
• 1997: March 20 at 8:54 a.m. EST (1354 GMT)
• 1998: March 20 at 2:54 p.m. EST (1954 GMT)
• 1999: March 20 at 8:46 p.m. EST (0146 GMT on March 21)
• 2000: March 20 at 2:35 a.m. EST* (0735 GMT)

In 46 B.C., Julius Caesar's consulting astronomer, Sosigenes, knew from Egyptian experience that the solar year was about 365.25 days in length. So to account for that residual quarter of a day, an extra day — leap day — was added to the calendar every four years. Unfortunately, the new Julian calendar was 11 minutes and 14 seconds longer than the actual solar year. By the year 1582 — thanks to the overcompensation of observing too many leap years — the calendar had fallen out of step with the solar year by 10 days. 
It was then that Pope Gregory XIII stepped in and, with the advice of his own astronomer, Christopher Clavius (1538-1612), produced our current "Gregorian" calendar. First, to catch things up, 10 days were omitted after Oct. 4, 1582, making the next day Oct. 15. In order to better adjust the new calendar format to more closely match the length of the solar year, most century years (such as 1700, 1800, 1900) — which in the old Julian calendar would have been observed as leap years — were not. The exceptions were those century years equally divisible by 400. That's why 1700, 1800 and 1900 were not leap years. 
But 2000 was a century year, evenly divisible by 400, so it was observed as a leap year. Had we skipped the leap year in 2000 (as in 1900), then the vernal equinox in 2000 would have occurred a day later, on March 21 at 2:35 a.m. EST (0735 GMT). 
Hence, the reason we have an asterisk next to that date. 
So, thanks to February having an extra day in 2000, the date of the equinox slipped back a day to March 20.