For the Northern Hemisphere, astronomical spring began today Monday, March 20th at 4:24 p.m. CDT with the arrival of the vernal equinox.

An equinox occurs twice per year. An equinox marks the day when the sun is passing directly over the celestial equato https://pbase.com/britestar/image/156516649 On the day of the equinox, the sun rises nearly-due east and set due west. North of the equator, the March equinox brings increasing earlier sunrises, later sunsets, and budding plants.

According to NASA, “Equinoxes and solstices are caused by Earth’s tilt on its axis and the ceaseless motion it has while orbiting the Sun. Think of them like events happening as our planet make its journey around the Sun. Earth has seasons because its axis is tilted. During the equinoxes, the sun shines equally in both the Northern and Southern Hemispheres."

Scientific explanation aside, our ancestors were more connected to the Sun than we are today. They observed its pathway across the sky, and they tracked how the sunrise, sunset, and day length changed, using the Sun (and Moon) as a clock and calendar. There are many ancient sites that mark the equinoxes (and solstices). In modern times, the “formal” first day of Spring in the Northern Hemisphere remains the day of the Vernal Equinox.

Meanwhile, meteorologists recognized March 1 as the first day of meteorological spring (in the Northern Hemisphere). That was based on annual temperature cycles and the Gregorian calendar. According to National Centers for Environmental Information (NCEI), the meteorological seasons were created because traditional seasons varied in length from 89 to 93 days and it was difficult for experts to compare statistics from one year to another. Meteorological spring is considered to encompass the months of March, April and May.

So, the month of March gives us two times that we can celebrate the arrival of Spring. Today is the official one.
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At the very beginning of the month on the first day of Meteorological Spring, I photographed a couple of members of our resident groundhogs: https://pbase.com/britestar/image/173447323

Today with the official arrival of Astronomical Spring, one of the groundhog girls (above) was back out sunning herself on top of the wood pile at the time of the Equinox.

At our house, the appearance of our resident groundhogs is a sign of Spring. Although Bella insisted that she saw one out of hibernation as early as February 10th, I spotted the first one of Mabel's pups on February 22 https://pbase.com/britestar/image/173430987 and then, the second pup on February 27 https://pbase.com/britestar/image/173443095

There is also still a third pup that has returned and also visits the woodpile where they all sunbathed together as babies back in 2020 https://pbase.com/britestar/image/170807928
Three years later, all of them are looking good and very healthy.

Last year, I spotted our first groundhog out of hibernation just one day before the Equinox. And the others after that https://pbase.com/britestar/image/172441787 Despite their waking up quite early this year, they all seem to be doing well and finding enough to eat.

I guess it really is Spring now. All we need now is some green grass, leaves on the trees, and flowers.