Temperatures could get close to 100 and feel higher than that Wednesday in the Lehigh Valley.

Heat index values of 104 are expected, and it could feel even hotter south of the region, according to the National Weather Service in Mount Holly, New Jersey.

Today’s high is expected to be in the 90s.

The Lehigh Valley, as well as neighboring Berks and Upper Bucks counties, is under a heat advisory from 10 a.m. to 8 p.m. Wednesday. Lower Bucks County and Philadelphia will be under an extreme heat warning at that time.

Forecasters recommend people stay hydrated and stay in air-conditioned rooms. Anyone going outside should wear lightweight and loose-fitting clothes, and outdoor activity should be limited to the early morning or evening hours.

Additionally, forecasters said there could be isolated storms across the Lehigh Valley and Poconos later Wednesday. Smoke from wildfires in Canada will likely be visible Wednesday as well, and could affect temperatures, the weather service said.

⚠️🥵 Extreme Heat Warnings & Heat Advisories are in effect for our entire area for Wednesday. Highs in the upper 90s to near 100° & max heat indices between 100-109° for most, including the NJ Shore & DE Beaches. Isolated storms possible late. (1/2) #PAwx #NJwx #DEwx #MDwx pic.twitter.com/wjQ33liMvx

— NWS Mount Holly (@NWS_MountHolly) July 14, 2026

There is a possibility of rain and storms over the weekend.

Here is the extended forecast from the National Weather Service:

Wednesday: Patchy smoke after 10 a.m. Increasing clouds and hot, with a high near 99. Heat index values as high as 104. West wind 5 to 10 mph, with gusts as high as 20 mph.

Thursday: Mostly sunny, with a high near 94. Light west wind increasing to 5 to 10 mph in the afternoon. Winds could gust as high as 20 mph.

Friday: Mostly sunny, with a high near 91.

Saturday: A chance of showers between 8 a.m. and 2 p.m., then a chance of showers and thunderstorms after 2 p.m. Partly sunny, with a high near 85. Chance of precipitation is 50%.

Sunday: Showers likely. Partly sunny, with a high near 87. Chance of precipitation is 60%.

Monday: A chance of showers. Partly sunny, with a high near 85. Chance of precipitation is 40%.