Thursday was another 90-degree day here in Pittsburgh.

Saturday, you might need a light jacket.

It's all part of the mystical meteorological makeup of Western Pennsylvania.

September started out hot enough with temperatures that were in line with one of the warmest summers we've seen lately. According to AccuWeather.com in State College, the average temperature for the three-month window of June through August was 2.9 degrees higher than the 73.6 we usually see.

That included 14 days in which the high temperature reached 90 degrees or more.

Thursday pushed that total to 15, as the thermometers at Pittsburgh International Airport ticked to 93 at midafternoon, just one degree shy of the all-time high for the date, set in 1953. It was the sixth time we've experienced 93 this year.

Still, that's a long way from the record, set in 1988, when we dragged our way through 38 days of 90 degrees or more.

Carl Erickson, a meteorologist with AccuWeather.com, said the average temperature for the past summer has been higher because many evenings, when the temperature dips, were a little bit warmer themselves.

Brian Jackson, director of service operations with Beverly Services for Heating and Cooling, said his Bethel Park company added three technicians to its crew of 15 this summer to deal with the surge in calls for air-conditioning.

"We've seen a substantial increase in business due to the hot weather," he said. "We've seen more busy days over this past summer than we've seen in a long time.

"This past Memorial Day weekend was probably the busiest that I can ever remember. Holiday weekends usually do get busy because people do more around their homes, and that was when the start of the hot weather really hit."

The Labor Day weekend, however, may offer a respite. The National Weather Service is predicting that today will be cloudy with a chance of evening showers. And Saturday's high probably won't inch out of the 60s.

Mr. Erickson said there's also the chance of gusting winds Saturday, sometimes as much as 30 mph, meaning you might have to pull that windbreaker out of the closet.

But don't blame Earl. According to Mr. Erickson, Hurricane Earl, which is spinning its way up the Atlantic coast, is not likely to affect Pittsburgh.

Thursday night, the National Weather Service downgraded Earl to a Category 2 storm with winds of 110 mph, and there were expectations that the hurricane might weaken further.

"It's running parallel to the eastern seaboard as it accelerates northward, grazing the Outer Banks," Mr. Erickson said. "It's not moving west, so the worst of the storm is out at sea."

Rains pounded much of North Carolina late Thursday as forecasters predicted a path that would take it north across the cape of Massachusetts on Saturday.

"It's not going to impact Pittsburgh at all," Mr. Erickson said. "If anything, it may actually limit the rainfall we would have seen with the cool front we have approaching. There may be a shower or thunderstorm around, but it won't be as bad as it might have been if Earl hadn't been out there."

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