State climatologist on why winter solstice is not our earliest sunset
Dec 21, 2022, 5:07 PM
(Photo courtesy of KIRO 7)
(Photo courtesy of KIRO 7)
Today marks the winter solstice, or the beginning of winter, for the Northern Hemisphere.
The winter solstice is the shortest day of the year, when the sun is at its southernmost point in the sky.
However, contrary to popular belief, it is not the day of the year with the earliest sunset or the latest sunrise. This varies by region, but in Seattle, our earliest sunset happened about 10 days ago.
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“Sunsets are getting a little later — they were the earliest a week-and-a-half, two weeks ago,” said state climatologist Nick Bond, a research scientist at the University of Washington.
If you haven’t noticed it, that is because the change is minimal. It is the difference between the sun setting at about 4:20 p.m. and 4:18 p.m. in Seattle.
Still, for those who hate the short afternoons, it is promising to know our region has been through the worst of them and has been on the upswing for more than a week. In contrast, our sunrises have yet to hit their latest point.
“Our sunrises are still getting a little bit later and later, and that’ll be the case until about the first of the year,” Bond said.
Bond explained that the reason behind this weird science has to do with the Earth’s orbit around the sun.
“The orbit around the sun — of the Earth, of course — is not perfectly symmetrical,” Bond said. “We’re actually closest to the sun this time of year and farthest away at the summer solstice and, of course, it’s the tilt of the Earth’s axis that determines the seasons. But that eccentricity in orbit is why there is that little quirk.”
While our days are now getting longer, our sunsets are getting incrementally later, and our sunrises will soon be getting earlier, Bond said it will be a while before we start to notice any progress.
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“For me, it’s more like toward the end of January,” Bond said. “You start noticing, ‘Hey, there really is a longer day here.’ And if you’re a commuter, you’re not driving to work in the dark and driving home in the dark.”
It is slow and steady — especially going into our coldest, wettest season — but it still means we are inching closer toward those long, golden June days.
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