Surprises about the returning Sun

(Photo by Dion Ogust)

Sunshine is now exploding back into our lives. For almost everyone, its light produces mood enhancement. But the process contains little-known quirks whose secrets are fascinating.

The overarching story, mentioned periodically on this page, is the fact that our region has an unusual sky situation. Many parts of the world have a rainy season; your friends in most of California, for example, enjoy cloudless skies in the autumn while their skimpy annual rain falls mostly during winter.

Like them, we see cloudy conditions certain times of the year, and get other months with just half as much cloudiness. And yet our rainfall shows no seasonal variation. We steadily receive between three and four inches of rain (or its snowfall equivalent) every month of the year, whether it’s a clear or a cloudy one. And that’s quite odd, don’t you think?

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Our cloudiest month is November. That’s when long-term records reveal an average 66 percent cloud cover. In November, the Sun only shines during 34 percent of the daylight hours. And since November daylight is very short to begin with, we end up with an average of only 3.4 hours of daily sunlight: the gloomiest month of the year.

December is slightly less cloudy, but we still only see the Sun during 39 percent of the day. And since this is the Solstice month, with the year’s least daylight, it translates into a daily pathetic December average of just 3.5 sunlit hours.

Those are our cloudiest months by far, and the darkest, too. If by New Year’s you somehow escaped suffering from SAD, or Seasonal Affective Disorder, you’re in luck, because things start to improve. After November’s depressing 34 percent, the sky’s percentage of clear skies during the year’s first four months is 51 percent in January, 52 percent now in February, 54 percent in March and 56 percent in April. Since the hours of daylight are rapidly growing, too, it translates into experiencing an average of 4.6 hours of daily sunshine in January, a nice boost to 5.7 hours now in February, 6.5 hours in March and 7.3 daily sunlight hours in April.

The current sunlight explosion period ultimately carries us to the four sunniest months of the year here in the Hudson Valley and Catskills. Those are May through August. During that entire period, the average daily cloud cover remains under 50 percent and the average daily sunshine stays over eight hours.

Around here, sunlight reaches its zenith in July. That’s when cloud cover is only 38 percent, our annual minimum, so that we enjoy 62 percent sunshine, which yields the year’s maximum of 9.3 average hours a day.

September falls off but remains pretty good, with 58 percent clear skies and seven hours of daily sunshine. But then the ebony axe falls. October in our region offers very nearly a 50/50 mix of blue sky versus cloud cover, which in that post-equinoctial month means that we only see a daily average of 5.4 sunlit hours.

That’s our normal year in terms of clouds and sun, which also reveals when we get the best stargazing. Obviously, you see more constellations and meteors in the warm weather than in the cold.

The biggest takeaway is what we are experiencing now, as February winds down: We are currently in the midst of a happy transformation in which, over the next five months, the skies grow steadily bluer and the hours of sunshine rapidly expand on a daily basis.

Want to know more? To read Bob’s previous columns, visit our Almanac Weekly website at HudsonValleyOne.com. Check out Bob’s new podcast, Astounding Universe, co-hosted by Pulse of the Planet’s Jim Metzner.

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