Yesterday was the first day of spring, but many of us have always believed the first day of spring is supposed to be on the 21st, which is today.
In fact, spring can begin on the 19th, 20th, or 21st, depending on the year.
So, what’s the deal? It all has to do with precise astronomical calendar keeping.
When Julius Caesar’s calendar estimated the Sun’s cycle for a year was 365.25 days, it was actually off a little.It’s actually 365.242 days.
The error amounts to almost 12 minutes per year, which doesn’t sound like much, but when you add it up, it’s almost a day per century and it has moved the beginning of spring for us to March 20th this year.
Last year, spring began on the 19th. The idea that spring always begins on March 21st is based on an old tradition but isn’t always an astronomical fact.
In fact, the last time spring began on the 21st was all the way back in 2007 and won’t happen again until 2101!