THE LOOP — If the thought of entering another Chicago winter isn't depressing enough, meteorologists say the city is on track to have one of the gloomiest Decembers in its history.

There has been no direct sunshine recorded in Chicago for 15 days this month, according to Frank Wachowski, who mans the official North West Side Midway Airport sunlight observatory.

Since Dec. 12, the city has seen only 33 minutes of sunshine, which peeked through the clouds Thursday.

Jen Sabella says it's been historically cloudy across Chicago:

That puts December 2014 on track to break the record for darkest December since 1975, when the National Weather Service recorded 19 percent sun exposure. As of Monday, Wachowski had recorded 16 percent sun exposure this month.

Meteorologist Frank Wachowski and the National Weather Service graphed this month's sunshine exposure data in the Chicago area. View Full Caption Courtesy Frank Wachowski

The record for darkest month ever in Chicago was November 1985, when sunlight hit the city for 16 percent of the month.

Percentages are determined by dividing the total number of hours between sunrise and sunset by the minutes of exposed sunshine recorded with monitoring equipment, Wachowski said.

Wachowski, 77, is a retired meteorologist, but since 1980 he has recorded sunshine data with official transistor sensors mounted atop his home in southwest suburban Burbank. He set up his home operation after the National Weather Service abandoned sunshine monitoring in the early 1980s, allowing him to keep the equipment and monitor data independently.

Wachowski said that in part, the lack of snowfall could be to blame. If a snowstorm blows through Chicago, the tightly packed cloud cover might dissipate. In the meantime, the clouds have been locked between a layer of cold air close to the ground with warmer air above the clouds.

"When you have an inversion, you have low clouds that stick around," Wachowski said. "Lack of wind contributes to giving us this situation," he said, along with unseasonably high temperatures, which this year have been 2 degrees to 2.5 degrees above average for December.

Essentially, "winds blew clouds in early in the month, and they stayed there," said Bill Nelson, a meteorologist with the National Weather Service who monitors the Chicago area.

Wachowski said there's an interest in tracking the sunshine shortage in part because of how extended periods of darkness can effect people.

"When it's cloudy like this, it does have an effect on people," he said. "It is kind of gloomy, you feel tired all the time."

Check out some of the depressing stock photography we found while working on this story.

Limited exposure to sunlight and Vitamin D common during the winter months can trigger a subtype of depression called seasonal affective disorder, according to a statement from Northwestern Medicine psychiatrist Pedro Dago, who studies the effects of sunlight deprivation at Northwestern University's Feinberg School of Medicine.

"SAD is not just a case of the winter blues, but a serious problem for many people, and it can be treated," he said.

Dago said treatments include sleeping more, eating healthily and exercising, and increasing exposure to sunlight, which might be tricky this month.

Wachowski also hypothesized that the temperature inversion — warm air below the clouds with cold air above them — could be contributing to the flu outbreak that's sickened Chicagoans and especially CPS students in large numbers this season.

"There seems to be a correlation, because when you have temps in the teens, you kill all the viruses and germs. Here, we have more moisture in the air," making it easier for germs to linger and spread, he said.

Weather patterns suggest that if any sunlight does peek out this month, it would be on Christmas Day, when a storm system might pass through Chicago, breaking up some of the cloud cover.

Still, Wachowski said it's "quite conceivable" that December 2014 will break the record set in 1975. So we've got that going for us, which is nice.

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