Sunrise, Sunset

If you are like me, you look forward to the winter solstice on December 21, when the days begin to lengthen again.  But if you treasure the early morning hours, about January 7 is the date to remember.  Not until then does the sunrise begin to come earlier.  I notice this when raising the flag each morning.  I often have to wait until it gets light enough.

Years ago, before the Internet and Google, I laboriously copied the sunrise and sunset times from our newspaper over an entire year.  When I plotted them on the same sheet of graph paper (to be thrifty), they formed two neat sine waves, coming together at the winter solstice and spreading apart the furthest at the summer solstice, as expected.  But the two waves were offset by about a month.  That I did not expect.

The winter solstice is the shortest day, but because of the earth’s tilt, sunrise time does not reverse until about January 7.  Sunset, on the other hand, reverses much sooner, about December 10.  The two are not in sync.  There are several weeks when both the sunrise and the sunset are coming later.  I already notice the later nightfall when taking down the flag.  Since Thanksgiving, I had been lowering it shortly after 4 as it was quickly getting dark, but now 5 is still quite light.

After the reversals, the first couple of weeks are still near the turning point of the curve, so the change is slight, only about a minute, but it soon picks up.  You should notice the earlier mornings as we get closer to February.  But remember the old saying, “When the days get longer, the cold gets harder.”

A simple Google search will turn up several sites that show sunrise/sunset times for your location.

RWalck@Verizon.net

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About Roger Walck

My reasons for writing this blog are spelled out in the posting of 10/1/2012, Montaigne's Essays. They are probably not what you think.
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