When I was a kid, I thought that the first day of spring was March 21st. When I met my husband, he informed me that the first day of spring is March 20th (his birthday). I checked the calendar, and, sure enough, March 20th said "First Day of Spring." Two days ago I was talking to my good friend, and she told me that she is updating her blog to a spring theme on March 21st, her birthday and also the first day of spring! (By the way, her blog looks beautiful!)
Okay, what is up with the first day of spring??? Being the curious person that I am, I decided to look it up. The first place I checked was my calendar, which said March 20th. I then decided to check out the trusty Internet. This site has the dates of the vernal equinox from 1980 to 2009: Vernal Equinox.
According to that site, spring was March 21st this year, that is if you compute it "in the Mathematica application package Scientific Astronomer, which is accurate to within only an hour or so, and in practice gives times that differ by up to 15 minutes from those computed by the U.S. Naval Observatory." (No, I can't translate - sorry!) It looks like the U.S. Naval Observatory agrees this year: Earth's Seasons, etc. 1992-2020. They give the time as 00:07 UT. Maybe the Mathematica or whatever is closer to the U.S. Naval Observatory than they thought since they give a time of 00:08 UT.
Just to make these extremely interesting figures more complicated, I live in Michigan, which is Eastern time, meaning that the vernal equinox was March 20, 2007, at 8:07 PM. However, I did my spring cleaning on March 21st, so that must have been the first day of spring! Wait! March 20th was warmer than March 21st, so that means the 20th must have been the first day of spring. Of course, how often is the first day of spring warm in Michigan? March 21st must have been the first day of spring!
Truly, I have a dizzying intellect! I think I'll stop since today is the 22nd anyway.