The date of winter solstice, when the time between sunrise and sunset is at its narrowest, arrives this year on Saturday, December 22. But by then, sunset will have already gotten a jump start on its journey toward spring.
According to the U. S. Navy’s sunrise/sunset table, tomorrow is the turning point for sunsets in 2011. At 5:08 p.m. eastern time, my hometown of Caledonia, Michigan, will witness its earliest sunset. From then on, while the sun will still set within the same minute for another five days, it will gain a handful of seconds each day until December 15, when it will set at 5:09.
By the time winter solstice arrives, sunset time will have increased by nearly three minutes, setting at 5:11. That’s here in Caledonia; sunrise and sunset times can vary surprisingly even within a single state.
So how come December 9 isn’t the shortest day of the year instead of December 22? Because sunrise, not prone to quitting its ways easily, continues to occur later and later, subtracting from our total amount of daylight at a faster rate than the sunset adds to it.
Following solstice, however, a reversal occurs. While the sun will still rise incrementally earlier for a while, sunset time will begin to outstrip it, gradually increasing our total daylight. On January 3, 2012, the sun will rise at its latest, somewhere on the far side of 8:13 a.m. here in Caledonia. After that, giving up reluctantly on its race after the sunset, sunrise time will begin to slowly retreat. On January 8, it will rise at 8:12; on January 12, at 8:11; three days later, at 8:10; and so it will go, with the sun rising earlier and setting later each day.
Don’t take that as a sign to trade your fleece jacket for a T-shirt; winter’s bitterest days still lie ahead. But for those of us in the northern hemisphere, our voyage toward summer will have gotten underway.