Today, March 20, 2017, is officially the first day of spring. Yes, that means sundresses are imminent. I know, it’s awesome. But what is the whole deal behind spring? We all know the weather starts to get warmer, but there’s gotta be more to it than that, right?
Yes, indeed there is. In fact, there’s a lot of interesting background information about spring that you can whip out to impress that cute girl in your afternoon lecture. Keep reading to get the full story behind spring.
What Is The Vernal Equinox?
An equinox is the moment in which the sun passes directly over the earth’s equator, which only takes place twice a year: March 20th and September 23rd. The 2017 spring equinox saw the sun hit that point at exactly 6:29 A.M. EST. Equinoxes are typically considered the start of a new season (spring and fall, respectively). On these days, day and night last roughly around the same amount of time. Pretty cool, right?
Though equinoxes are used to designate the astronomical changing of the seasons, meteorological seasons are based on the annual temperature cycles. A meteorological calendar is split into four seasons of roughly the same length, and note March 1 as the first day of spring. However, everyone who just survived that massive blizzard last week knows that is not the case. Then again, only the northern hemisphere is celebrating the beginning of spring today.
The equinoxes are the only time of the year when the edge between night and day is perpendicular to the equator, giving us that 12-hours of light and 12-hours of darkness timeframe.
Julius Caesar set March 25 as the spring equinox when he established the Julian calendar in 45 BC. However, because the Julian calendar was slightly longer than a typical year (365.25 days), the equinox dates began to ship. This spurred Pope Gregory XIII to create the modern Gregorian calendar, which placed the spring equinox around March 20-March 21.