Heat index may jump above 100 degrees; rain coming this weekend, forecasters say

Extreme heat is back with temperatures expected soar past 90 degrees Thursday, according to Jared Rackley, a meteorologist with the National Weather Service in Moon.

Pockets of the region could see a heat index — that’s how hot it feels taking the humidity into account — above 100 degrees on Thursday. The forecast is hot enough that Allegheny County Health Department issued a code red alert, which opens cooling centers in the county. They’re listed here. Click on the plus next to code red information.

And even though a bit of cooler weather is on the way, it’s going to bring the rain back with it.

Pittsburgh is expected to see the daily high temperature drop slightly, from 93 degrees on Thursday to 89 on Friday and 85 on Saturday, with lows in the mid-70s at night.

The recent weather has been sweltering but it hasn’t come close to setting any records for the region.

“We actually only hit 90 degrees twice in July,” Rackley said, although Thursday’s forecast is likely to bump that figure up to three. “It’s the humidity we’ve had that makes it feel hotter than it is. You can get increasing heat indices even though the temperature is slightly cooler.”

The heat returns to close out the week. Heat indices on Thursday are forecast to reach the mid to upper 90s, and even touching 100 in spots, with highest confidence currently in eastern Ohio where a Heat Advisory has been issued from 11am-8pm Thursday. Stay cool and hydrated! pic.twitter.com/vPpwQMtRmA

— NWS Pittsburgh (@NWSPittsburgh) July 23, 2025

Friday, Saturday and Sunday could also include rain and thunderstorms that will temper how hot it gets, at least for a time, Rackley said.

“We’re going to slowly ramp back up,” he said. “Sunday will be in the upper 80s across most of the region, but we have 90 degrees in the forecast for Monday.”

The National Weather Service’s hazardous weather outlook also warns of the possibility of flash flooding resulting from excessive rainfall across a wide swath of Western Pennsylvania.

A front will move into the region for Friday and Saturday. A Marginal Excessive Rainfall Outlook is in effect for both days. Thus, due to heavy rainfall or training, minor flooding is possible. pic.twitter.com/vFpITCUyqD

— NWS Pittsburgh (@NWSPittsburgh) July 24, 2025

Unlike the last storm that brought flooding to the region, the Pittsburgh area hasn’t gotten much rain in July, which means the ground is able to absorb a good deal more storm water.

“But the possibility of getting 1.5 or 2 inches of rain in an hour is going to overcome any sort of flash-flood guidance we issue,” Rackley said.