OK, so it may not feel like it today when we only top out with a high of 39, but it is the first day of spring. But fear not, warm weather is one the way. It’s interesting to note that meteorologists actually mark two different first days of spring. The say the meteorological first day is March 1st, when they feel the actual weather starts to turn, and the astronomical first day of spring, which is today. So what makes this Day One of spring? Here’s everything you need to know:
1. What happens on the first day of spring?
The first day of spring is the only time of year when the sun rises in the east and sets in the west for everyone across the world. It’s also the only moment each year that the Earth’s tilt is zero in relation to our sun. So, if you were standing on the equator, the sun would pass directly over your head.
2. How do you determine the first day of spring?
The first day of spring is determined by the vernal equinox, which is when the sun crosses over plane of the earth’s equator, making night and day approximately equal lengths all over the world. One the day of the equinox passes, both of Earth’s hemispheres get an equal amount of sunlight.
No. The date changes each year since it is determined by the timing of the sun crossing over the Earth’s equator, which shifts ever so slightly depending on a few factors. The Earth’s orbit is constantly changing in relation to the sun, while at the same time the gravity of other planets impacts the Earth’s location in space. Those physical dynamics coupled with the fact that each calendar year always has a different number of days (think leap years), means that the first day of springs varies slightly from year to year.
4. What time does spring arrive today?
The exact time the vernal equinox is supposed to occur this year is at 12:15 p.m. on Tuesday, March 20, according to the Farmer’s Almanac.
Bu the way, the spring equinox in the Southern Hemisphere happens at the exact opposite time of the year, so it’s actually the fall equinox for people on the other side of the world (the same way that winter and summer are reversed for both hemispheres).