The record-high temperatures that have affected swaths of North America, including the Pacific Northwest, where an alarming and historic heat wave has caused hundreds of deaths, have signaled to health and environmental experts that the public needs to know how to deal with extremely hot weather.

“As we move forward into essentially a hotter planet, we need to really rethink heat as a risk,” said Sabrina McCormick, an associate professor of environmental and occupational health at George Washington University. “Everyone is vulnerable, and these exposures can creep up and unexpectedly affect you, so you need to really keep an eye on it.”

Below we’ve compiled answers to frequently asked questions about extreme heat, as well as tips from experts for how to best protect yourself and others this summer and beyond.

What to know

  • What is extreme heat?
  • What heat-related conditions should I watch out for?
  • How can I stay safe in extreme heat?
  • Who is at increased risk of being affected by heat?
  • If I feel sick or notice someone who isn’t well, what should I do?