– How is it possible that the sun rises at the same time (7:50) from December 27th through January 8th in Portland, OR?
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It’s usually not *exactly* the same time. If you look at when the sun rises to the second or fraction of a second it wouldn’t be exactly the same through all those days.
But we might expect more change than a second or two. There are two things going on here:
First, the day length is changing. That part is usually pretty obvious: days are longer in the summer and shorter in the winter.
Second, when the center of the daylight is changes, too! Solar noon (when the sun is highest in the sky, the middle of the day) isn’t at the same time every day.
So if the days are getting longer we would expect that sunrise would get earlier. But if solar noon gets later proportionally, then sunrise may be at approximately the same time, or even get a little later while the days get longer. The opposite is true for sunset: if the days are getting longer and solar noon is getting later, then sunset will get much later!
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