It is sometimes reassuring to hear that things are objectively as bad as they seem.
So perhaps Pittsburghers will take some comfort in a recent analysis that confirms as dreary weather goes, we’re hard to beat.
Last week, climatologist Brian Brettschneider crunched numbers from thousands of weather data points in a quest to determine the dreariest weather in America. Pittsburgh finished tied with Portland for second place, behind first-place finishers Seattle and Buffalo.
“It’s not meant to be a slight for anyone high on the list,” said Mr. Brettschneider from his home in relatively ungloomy Anchorage, Alaska. “As a climate scientist, I churn the numbers and let the chips fall as they may.”
For his “dreariness index,” Mr. Brettschneider considered average cloud cover, total annual precipitation and days per year with measurable precipitation, giving equal weight to each. For each city, he ranked each factor from 1 to 10 and then added up the rankings for a total of 30 possible points.
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Pittsburgh wound up with a 26 — 7 for total precipitation, a 10 for the number of wet days and a 9 for cloudiness — finishing one point behind Buffalo and Seattle, which each scored 10s for cloudiness.
Pittsburgh’s cloudiness is most striking in the winter: December and January days average more than 78 percent cloud cover, he said, compared with a (still cloudy) 57 percent in August and September.
The least dreary cities included Bakersfield, Calif., Las Vegas and Phoenix, Ariz.
The project started with Mr. Brettschneider, who writes a climate blog, wondering about the claims of Seattle residents to live in such a rainy city. He generated a map showing that, in reality, 40 percent of the country receives more precipitation than Seattle — a map that was picked up on websites for publications such as The Washington Post and The Atlantic.
Commenters noted that it wasn’t so much the amount of rain in Seattle, but the dreariness, leading Mr. Brettschneider to come up with a new metric — one he admits isn’t particularly scientific.
“Some people said it’s the amount of rain, some said it’s how cloudy, some said it’s how often it rains,” he said. “It’s a fool’s errand to try to come up with anything that resembles a scientifically derived formula — it’s just kind of a gut feeling.”
Pittsburgh’s persistent cloudiness and frequency of precipitation can be explained, in part, by its location in between Lake Erie and the Laurel Highlands, said Tom Green, a meteorologist with the National Weather Service. Wind coming from the west picks up moisture over the lake and that cold, wet air mass has trouble continuing east past the Laurel Highlands.
“In the winter, we’ll have a cold air mass that generally kind of wants to sink,” he said. “It won’t be able to rise as easily up and over the mountains — the airflow gets blocked, essentially.”
Mr. Green noted that on winter days, it’s common to see satellite pictures of a cloudy Western Pennsylvania, followed by sun on the eastern side of the mountains.
Mr. Brettschneider did not include other weather unpleasantries, such as coldness or high winds, into his analysis. “I wasn’t trying to make an index with a negative connotation,” he said. “It just ended up that way.”
First Published: March 24, 2015, 4:00 a.m.
