Winter Solstice: A Time to Celebrate
|By: Angela Fritz, 07:23 PM GMT del 21 Dicembre 2011||+10|
Tomorrow, December 22nd, is the Winter Solstice: the shortest day of the year, and what we like to refer to as the first day of winter.
But what does that really mean? Hasn't winter already started? In the U.S., it came in with a bang but has since tapered off to a whimper. One week ago, on December 14th, the only place that fell below zero was Big Piney, Wyoming with a low of -2°F. That's pretty mild for December in the lower 48!
But in Europe, winter has already taken its toll. Last week, winter storm "Joachim" tore through western Europe, leaving as much as 5 feet of snow in its wake. Joachim's lowest central pressure got down to 963.8mb, and wind gusts up to 105mph (175 kph) were recorded.
From Christopher C. Burt's blog on Joachim:
Widespread wind damage in northern France brought down power lines resulting in 400,000 homes losing electricity. A large Maltese cargo ship, the TK Bremen, was washed ashore by 25-foot English Channel seas landing on the coast of Brittany. The crew was safe but some 200 tons of fuel oil leaked from the vessel.
So why do we wait so long to declare winter?
The first day of "meteorological winter" is December 1. Meteorologists like to break the year up into three-month chunks, which happen to coincide with the four seasons. Winter, for us, is December, January, and February. But traditionally, the rest of the world declares that winter begins on this, the shortest day of the year.
At 12:30am ET (5:30am GMT) on December 22, the sun is directly over the Tropic of Capricorn, which is 23.5 degrees south of the equator. For the Northern Hemisphere, the sun on this day is at the lowest point from in the sky for the entire year. The word "solstice" comes from the Latin word "solstitium," which literally means "the sun is standing."
During the Northern Hemisphere's Winter Solstice, the sun is centered over the Tropic of Capricorn—23.5° south. (Image source: Wikipedia)
For places in the Southern Hemisphere like Australia, Chile, Brazil, and southern Africa, it's the longest day of the year, and they're (usually) basking in warm summer weather.
But for us in the Northern Hemisphere, we're trying to get through a brutal winter that's only just started. Although the days will get longer from now until June, we won't see the temperatures and snow turn the corner until March. That's because temperature tends to lag the amount of sunlight we receive. The lowest temperatures are recorded about a month after the winter solstice, and the highest temperatures about a month after the summer solstice in the third week of June.
It's no surprise that many of our most important festivals and celebrations fall close to the winter solstice. It's the time when the nights get shorter and the days get longer, and culturally it symbolizes rebirth. Today begins the trend of longer days, shorter nights, and the migration of the Sun back to the Northern Hemisphere.
So, there's something to help you get through the rest of winter. Summer is just around the corner.
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Atmospheric Scientist here at Weather Underground, with serious nerd love for tropical cyclones and climate change. Twitter: @WunderAngela
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