This week is a good news, bad news situation.
The bad: the earliest sunsets of the year happen this week in Boston.
The good: in just a few days, sunsets start getting later.
On Tuesday and Wednesday, the sun sets in Boston at 4:11 PM. Sunset times start getting later beginning on Thursday.
Unfortunately, we continue to lose daylight through the Winter Solstice on December 22. On that day, we enjoy just 9 hours and 4 minutes of light. Even after that point, sunrises will continue to get later, too. The earliest sunrises occur during the first week of January.
It’s a common misconception that the latest sunrise and earliest sunset occur on the same day, on the first day of winter.
The difference stems from the way we measure time. On a watch, a day is exactly 24 hours. Scientifically, a day stretches from one solar noon to the next. Solar noon is the time at which the sun reaches its highest point in the sky on any given day.
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As you might guess, solar noon is not exactly 24 hours in length. It varies over the course of the year. During the winter, it’s a little bit less than 24 hours.
So, the built up difference between our measured day and the solar day creates an offset between the latest sunrises and earliest sunsets.
