December is an interesting month. It’s a month that can provide some of the most interesting and dramatic winter landscapes of the season and it’s when you feel winter is upon us. But what is funny, December looks like winter but technically it’s not winter. Let me explain. The first day of winter is actually December 21st at 6:04 AM in the Northern Hemisphere. The winter solstice! This is at the end of the month! So how can the entire month of December be considered winter?
I think most people consider December as being part of winter. And you would be mostly right if you thought this since the meteorological first day of winter is December 1st. This is different from the solstice. It’s the day that most meteorologists consider the start of winter or at least the winter weather season. I say, good enough for me.
Getting back to the solstice. The solstice is an astronomical event that occurs twice a year. Once in the spring and once in the fall. Every day the earth is tilting on its axis either towards the North Pole or towards the South Pole depending upon the time of year. The axis is the imaginary line drawn through the earth from the North Pole to the South Pole.
At this time of year the earth tilts on its axis moving the northern hemisphere (us) away from the sun and exposing the southern hemisphere more to the sun. The furthest the earth tilts is 23.5 degrees north or south of the equator, or about a quarter angle to the sun. When we reach the end of our movement north or south the tilting comes to a stand still, which is called the solstice. The name solstice comes from the Latin, sol (sun) and sistere (to stand still).
Believe it or not, just that small amount of tilting away from the sun is enough to give us winter or summer. What makes it more mind boggling is the earth revolves around the sun in an elliptical pattern and during winter we actually move closer to the sun by over 2 million miles than we are in summer. So even though we are closer to the sun in winter the angle or title of the earth is enough to plunges us into the cold depths of winter.
Adding to Decembers interests, this year on December 1st we had a very interesting celestial event. The planets of Venus and Jupiter were seen lined up with the moon in the night sky. This is known as a planetary conjunction. The lining up of these planets only happens once every 13 months. Venus and Jupiter are our brightest planets making this conjunction an amazing sight. Just after sunset and lasting for only a couple hours the crescent moon, Venus and Jupiter we so bright and obvious that anyone with clear skies and the inklings to look up were treated to a very cool celestial show. I know I spent nearly an hour looking and photographing the night sky event.
So with snow blanketing most of the upper Midwest and temperatures that force us to wear hats and gloves, I would say that December is definitely a winter month no matter if you consider winter starting at the first of the month or the 21st. Until next time…