SUMMIT COUNTY — Given the unusual early heat wave that’s gripped most of the country, perhaps it’s fitting that the spring equinox makes it’s earliest arrival in more than 100 years — since 1896, to be exact.
In the mountain time zone, the moment of equinox is actually late Monday night, which means it will officially be spring by the time you wake up.
It’s also a day you can check your iPhone GPS and compass against the sky because the sun rises due east and sets due west.
The equinox marks the moment when the sun is directly above the Earth’s equator. Days and nights are about equal in length in both the northern and southern hemispheres — but not exactly the same, as some people believe.
The exact time and date of the equinox changes for very simple reasons. The division of the year into 365 days doesn’t exactly match up with celestial rhythms. The Earth’s orbit around the sun isn’t exactly circular. This archaeoastronomy website has detailed info on the timing of equinoxes and solstices.
But the simplest reason for this year’s early arrival is that it’s a leap year. If it weren’t for the extra day in February, the equinox would be arriving March 21. If you’re still confused, check this link at the U.S. Naval Observatory website — it may help clear thing up, or leave you more confused.
So the seasons aren’t exactly equal lengths. Here’s how they shake out, according to Space.com:
Winter: 88.994 days
Spring: 92.758 days
Summer: 93.651 days