• Dangerous heat and humidity could affect much of the eastern U.S. from July 2 through at least July 5.
  • NOAA says the highest risk areas include parts of the Mid-Atlantic, Southeast, Ohio Valley, Tennessee Valley, Great Lakes, and Middle Mississippi Valley.
  • The American Red Cross advises people to stay hydrated, stock up on supplies, find air-conditioned spaces, learn heat illness warning signs, and monitor local alerts.

Fireworks, beach trips, and backyard gatherings are staples of the Fourth of July holiday. This year, however, many Americans may need to add heat safety to their plans. Forecasters say a prolonged stretch of extreme temperatures and high humidity could affect much of the country heading into the holiday weekend.

Here's everything you need to know.

Which areas could see the most extreme heat?

Leading up to and through the July 4 holiday weekend, much of the eastern half of the United States could face dangerous heat and humidity, according to a new outlook from the National Weather Service (NWS), part of the National Oceanic and Atmospheric Administration (NOAA). The high temperatures are expected to last from July 2 through at least July 5.

“Significant, dangerous heat wave expected next week for the
Central to Eastern U.S., the agency stated.

A high risk of extreme heat is in place for parts of the Mid-Atlantic and Southeast from July 2 to July 4, as well as portions of the Ohio Valley, Tennessee Valley, Great Lakes region, and Middle Mississippi Valley from July 2 to July 3. A broader moderate risk extends across much of the central and eastern U.S.

How hot will it feel?

The biggest concern is the combination of heat and humidity. Forecasters say heat index values, or what the temperature feels like when humidity is factored in, could exceed 100°F to 105°F in many locations. Some areas may also approach or break daytime temperature records.

While normally we’d expect temperatures to lower during nighttime, forecasters are saying that overnight conditions will be just as balmy as temperatures are expected to remain in the upper 70s and lower 80s across some regions.

How to stay safe during a heat wave

The timing is especially concerning because millions of Americans are expected to spend time outdoors for holiday celebrations, including fireworks shows, barbecues, parades, and other events.

The American Red Cross recommends taking the following precautions during extreme heat:

  1. Stay hydrated: Drink enough water and avoid sugary and caffeinated drinks.
  2. Gather supplies in case of an emergency. Because it’s a holiday, some stores might be closed. Be sure you have water, medicine, food, and anything you might need in the event of a power outage.
  3. Stay cool. According to the American Red Cross, fans may not be enough to stay cool. If you don’t have an air conditioning unit, it recommends trying to move to an air-conditioned location to prevent heat-related illness. You can visit the National Center for Healthy Housing to find the closest cooling center near you. Libraries and malls are also an option.
  4. Recognize heat stroke. It recommends learning how to recognize and respond to heat illness. According to the Centers for Disease Control and Prevention (CDC), signs of overheating include:
  • Muscle cramping
  • Unusually heavy sweating
  • Shortness of breath
  • Dizziness
  • Headaches
  • Weakness
  • Nausea
  1. Stay connected: Sign up for local emergency alerts and keep an eye on weather forecasts and news updates.
Headshot of Rosamelia Sánchez Lara
Rosamelia Sánchez Lara
Temporary Writer

Rosamelia is a writer at Good Housekeeping, covering everything related to Gen Z, lifestyle, and online trends. She’s a graduate of NYU's Magazine and Digital Storytelling program. In her free time, you can find her reading and reviewing books on her bookstagram: amelias_biblioteca.