Light will be fleeting today. Darkness will linger.
It is the first day of winter, an astronomical milestone and official end to autumn when the sun shines directly on the Tropic of Capricorn, robbing the Northern Hemisphere of daylight.
The winter solstice marks the shortest day — and longest night — of the year. Today is 3 hours, 22 minutes shorter in Palm Beach County than on the summer solstice in June.
Alan MacRobert, senior editor of Sky & Telescope magazine, said the exact time of the solstice is 11:48 p.m. That’s when the sun reaches its farthest point south for the year and begins its 6-month return northward.
“In cultures around the world and throughout history, it’s celebrated with rituals of light in the darkness and the promise of renewal and rebirth, as the sun begins returning for another spring and summer to come,” MacRobert said.
Although South Florida’s day will be more than three hours shorter than during the summer solstice, more northern realms will see even less sunlight.
In New York, the day will be more than 5 hours shorter.
“New York is closer to the poles than we are,” said Sam Storch, a retired astronomy professor and member of the Astronomical Society of the Palm Beaches. “It’s a much more extreme difference, much more dramatic.”
The winter solstice this year also corresponds with the Ursid meteor shower, which peaks overnight tonight and Tuesday.
The Ursid shower comes on the tail of the more famous Geminids, and both should be visible with clear dark skies tonight. With the moon in its waxing gibbous phase at about 83 percent full, the Ursids will compete with the lunar brightness.
But EarthSky.org said the Northern Hemisphere will offer the best viewing. The meteors radiate from near the star Kochab, in the bowl of the Little Dipper.
“This shower has been known to produce short bursts of over 100 meteors per hour,” EarthSky blogger Bruce McClure wrote. “But typically, the shower is much sparser than that. In a dark sky, it may produce five to 10 meteors per hour at its peak.”
Besides the light from the moon, the weather may not cooperate for the Ursid shower.
Tonight is expected to be mostly cloudy with a 30 percent chance of rain. Tuesday night looks to be much of the same.
The weather also doesn’t seem to care much what the calendar — astronomical or meteorological — says.
The meteorological beginning of winter is Dec. 1. Weather forecasters use meteorological seasons, which are grouped by months. Meteorologically, winter is December, January and February. It’s a more efficient measurement than using fractions of months and is based on the annual temperature cycle over the position of the Earth in relation to the sun, according to the National Centers for Environmental Information.
While the normal high temperature for Dec. 21 is 76 degrees, today is expected to be closer to 80 degrees with a low tonight of just 74 degrees. If it really does only hit 74 degrees, that would beat the overnight warm record of 76 degrees set in 2013.