Pittsburgh residents have been known to wear swimsuits and winter jackets during the same… Pittsburgh residents have been known to wear swimsuits and winter jackets during the same week. Pittsburghers could have worn jackets on the morning of June 11, when the temperature fell to 42 degrees. One week later, the afternoon temperature reached 87 degrees and they could take their swimsuits back out.

“That kind of weather is not uncommon,” said Dr. Greg Faiers, associate professor of geography at Pitt’s Johnstown campus. “Pittsburgh’s weather is like a yo-yo, but that’s because the closer a city is to an ocean, the less likely it is to have fluctuating temperatures.”

Pittsburgh is the third cloudiest city in the United States, according to CityRating.com, and averages only 59 clear days per year. Pittsburgh’s proximity to water has a lot to do with its unusual weather.

“The Ohio River, splitting into the Monongahela and the Allegheny, brings sources of moisture and coolness into the heart of Pittsburgh,” said Donald Rosenfeld, a 20-year member of the American Meteorological Society. “That affects both summer afternoon temperature with cool river breezes and increased humidity, which may not be so desirable.”

Rosenfeld explained that cloudy days and showers are related to the wind’s direction and location of large water sources anywhere from 15 to 50 miles from Pittsburgh.

“Combine Lake Erie, the Atlantic Ocean and the topography of the Pittsburgh area, [through] the jet stream and mean storm tracks,” he said, “and you have the ingredients for a lot of cloudiness.”

Oceans can help steady temperatures by absorbing heat during the day and releasing it at night. But Pittsburgh can only count on the water of the three rivers.

Although Pittsburgh is nearly 500 miles west of the Atlantic Ocean, its extreme temperatures come from being farther from large bodies of water, such as an ocean. The further inland a city is, the more its weather tends to rise and fall swiftly.

Seattle, for example, is less than 100 miles east of the Pacific Ocean and experiences little rainfall in the summer. It doesn’t have the extreme rise and fall in temperatures during the year that Pittsburgh does.

Rob Kaczorowski, the assistant director of operations for Pittsburgh’s Public Works, said he has witnessed his share of severe outdoor weather in Pittsburgh. The best weather to work in, according to Kaczorowski, are temperatures in the 50s and 60s, and the worst is anything higher than 70. For six to eight hours per day, public workers are outside, vulnerable to the day’s weather.

“Any type of disruption from Mother Nature causes us to change our task for the day,” Kaczorowski said. “In the winter we patch potholes, but if it snows, then we’ll have to go into snow-removal team. We have to react to the weather constantly.”

Pittsburgh averages 36.9 inches of rain per year, about one inch less than Seattle. But in the summer, Pittsburgh has quick, sporadic showers.

When a city is south of a low-pressure system, like Pittsburgh is during the summer, rain won’t wash out a visitor’s outdoor plans, as long as he is prepared for the weather they will find.

“It might be a cool day, a showery day or a day in the 80s or 90s,” Faiers said. “Just don’t assume that because it’s summer in Pittsburgh you’ll be wearing shorts.”