Dangerous heat grips the East, Midwest, and West as New York nears 100, Baltimore feels 103

A wide swath of the United States is dealing with oppressive heat and sticky air, and officials have issued advisories in parts of California, the Midwest, and much of the Northeast.

The next week could bring more than just uncomfortable weather. In some places, extremely high temperatures are expected to coincide with evening storms, posing serious health and safety risks.

What's happening?

Multiple regions are under heat alerts as the mix of high temperatures and humidity creates hazardous conditions.

In the Bay Area, cities including San Jose, Oakland, and Fremont could reach temperatures over 100 degrees, according to ABC News, while California's Central Valley could see readings near 105 in Bakersfield and Fresno through Saturday.

As ABC News reported, parts of the Midwest were also under advisories Thursday, including Detroit; South Bend, Indiana; and Cleveland, where the heat index, or what temperature feels like, could reach 100 degrees.

Friday's humidity is expected to push heat index temperatures above 100 in Philadelphia, Washington, D.C., and Raleigh, North Carolina, with possible record highs in those regions. In New York, the heat index could reach 99 degrees, while Baltimore could see a high of 103 degrees. 

ABC News warned Northeast commuters to prepare for severe thunderstorms. 

Why does it matter?

Extreme heat is one of the deadliest forms of weather because it can affect people quickly, especially older adults, children, outdoor workers, and anyone without reliable air conditioning.

High humidity makes conditions even more dangerous by limiting the body's ability to cool itself, increasing the risk of heat exhaustion and heat stroke.

Worsening extreme weather disasters can threaten lives and livelihoods by putting pressure on hospitals, disrupting transportation, damaging crops, and driving up electricity demand and utility bills.

That can mean dangerous commutes, canceled outdoor work or events, and higher risks for pets and vulnerable neighbors. It can also strain local infrastructure as roads, transit systems, and power grids operate under intense stress.

If you're trying to understand how weather patterns are changing, exploring critical climate issues is a great place to start.

What can I do?

Plan any outdoor activities like running errands or work for cooler hours if you can, keep hydrated, wear lightweight clothing, and spend time in air-conditioned spaces when possible.

Especially in the Northeast, keep an eye on local alerts for evening storm warnings, transit disruptions, and available cooling centers. If you need to be outside, take frequent breaks in the shade, and never leave children or pets in parked cars.

Reach out to neighbors who may need extra help, especially older adults and people with health conditions, and make sure pets have cool water and shelter. Heat illness can include dizziness, nausea, confusion, and a rapid pulse.

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