Jul 21, 2022 - Science

Over 100 million under heat warnings and advisories in U.S.

A woman wiping her brow in New York City on July 21.

A woman wipes her brow in New York City on July 21. Photo: Spencer Platt/Getty Images

Over 104 million people are under heat warnings and advisories across the U.S. on Thursday as dangerous heat continues to roast the southwest, south-central, and eastern U.S. according to the National Weather Service (NWS).

Why it matters: Excessive heat events are the leading weather-related killer in the U.S. and can greatly strain the power grid, leading to power interruptions. Climate change from greenhouse gas emissions is causing heat waves to be more severe, frequent and longer-lasting.


  • Much of Oklahoma and Texas are under a heat advisory after being under an excessive heat warning the past two days.
  • Parts of Arkansas, Louisiana and almost all of Alabama are under a heat advisory and an excessive heat warning. Heat index values will reach near 110° Fahrenheit in western Alabama.
  • All of Mississippi is under a heat advisory and an excessive heat warning, with heat indices expected to reach 110°F and temperatures in the mid to upper 90s.


  • Western Arizona, southern Nevada and southeast California are under an excessive heat warning through Friday. Temperatures in Phoenix are set to reach 110-115°F through Friday, while highs in Las Vegas could reach 112°F on Thursday and 113°F.

East Coast:

  • Heat advisories are in place from the eastern Carolinas to New England and daily highs will likely remain in the upper 90s and lower 100s from Richmond to Boston.
  • Hot, humid air is expected to remain in place along the East Coast before a cold front brings showers and storms to portions of the Northeast and Southeast.

Thought bubble, via Axios' Andrew Freedman: Global warming from the burning of fossil fuels, such as coal and natural gas, is greatly increasing the odds of heat waves, their severity and longevity.

  • What is happening now is not typical summer weather. Parts of the Plains, for example, are seeing their hottest summer on record so far, with temperatures well above average.

The big picture: The NWS said above-normal temperatures are expected to continue across much of the U.S. through the end of the week.

  • A huge swath of the U.S. West, South and Northeast on Thursday saw elevated low temperatures that climate change has made between three and five times as likely to occur, according to Climate Central's Climate Shift Index.
  • Abnormally high nighttime temperatures can increase the risk of heat-related hospitalizations and deaths because prolonged stretches of hot weather prevent people from cooling off from the day’s heat.

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