Philadelphia area expected to see a warmer and wetter summer than normal

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Temperatures in Philadelphia are expected to top 90 degrees on Thursday for the first time this season.

Forecasters say to expect a hot summer.

“It’s been warm the last couple years for sure,” said Mike Lee, a meteorologist in the National Weather Service forecast office in Mount Holly, New Jersey. “It’ll stay fairly warm.”

The National Weather Service predicts that southeastern Pennsylvania, Delaware and South Jersey will experience a warmer and wetter summer than normal.

“It certainly doesn’t mean that every single day is going to be a heatwave or every single day is going to be … 90, 100 degrees,” Lee said. “It’s more so that in terms of the overall weather patterns, it’s going to be favoring warmer days. So we could see more 90-degree days than we typically do over the summer season.”

This year’s first 90-degree day has come later in the season than usual, Lee said.

This summer’s above-normal forecast for temperature is more certain than the forecast for precipitation, said Sarah Johnson, another meteorologist at the Mount Holly forecast office.

“For precipitation, there isn’t quite as strong of a signal,” she said.

In 2023, El Niño drove record-high global temperatures. But since then, the El Niño–Southern Oscillation, which changes ocean temperatures in the Pacific, has shifted to La Niña and then neutral conditions. 

This summer, weather patterns are expected to bring moisture and warmth up from the Gulf to the Philadelphia region, Pennsylvania State Climatologist Kyle Imhoff said.

The forecast comes on top of rising temperatures due to climate change. According to the research by nonprofit Climate Central, average summer temperatures in Philadelphia have trended up by roughly 3 degrees since 1970. It’s too soon to say what role climate change may play in hot temperatures this summer, but the baseline has shifted, Imhoff said.

“We’re starting off already at an elevated level,” he said. “So if we’re saying warmer and wetter than typical, well, the typical has gotten warmer and wetter.”

Code Orange air quality warning for Thursday

The Pennsylvania Department of Environmental Protection issued a Code Orange air quality alert for Thursday afternoon, warning of elevated levels of ozone pollution. Code Orange indicates that air quality may be unhealthy for sensitive groups, including older adults, young children and people with lung conditions such as asthma.

Officials say the hot temperatures combined with low levels of smoke from Canadian wildfires will produce “significant ozone concentrations.”

People who are sensitive to poor air quality should limit their activity outside.

The Code Orange covers Philadelphia, Bucks, Chester, Delaware and Montgomery counties.