Know your heat terminology: Extreme Heat Warning, Extreme Heat Watch and Heat Advisory
The National Weather Service has retired the terms "Excessive Heat Watch" and "Excessive Heat Warning" and replaced them with the terms "Extreme Heat Watch" and "Extreme Heat Warning."
Understanding heat alerts
FOX Weather Meteorologist Craig Herrera explains new heat alert terminology that is now being used by the National Weather Service: Extreme Heat Watch and Extreme Heat Warning.
The National Weather Service is using new heat alert terminology during the summer to improve public awareness and understanding of what the weather service says is the leading cause of weather-related deaths in the country, annually.
The agency has retired the terms "Excessive Heat Watch" and "Excessive Heat Warning" and replaced them with the terms "Extreme Heat Watch" and "Extreme Heat Warning."
HEAT ALERTS ARE GETTING NEW NAMES THIS SUMMER FROM NATIONAL WEATHER SERVICE
This graphic shows the new heat alert terminology being used by the NWS.
(FOX Weather)
An Extreme Heat Watch indicates that dangerous heat is possible in the coming days. Under an Extreme Heat Watch, the NWS advised people to reschedule upcoming outdoor activities and make sure that vulnerable populations, such as children, seniors and pets, have a place to get relief from the heat.
A Heat Advisory means that dangerous heat is expected within 12 hours.
An Extreme Heat Warning means that dangerous heat is occurring or about to happen. Under this alert, the NWS advises people to stay hydrated and find a cool indoor area to seek refuge from the blistering sun.
The NWS said in a news release that the term "extreme" conveys the danger of the threat better than the word "excessive."
The change in verbiage went into effect in March 2025.
This graphic shows the current definitions of heat alerts issued by the National Weather Service.
(FOX Weather)
The FOX Forecast Center emphasizes that the effects of heat on our bodies are not just determined by air temperature but by the humidity and several other factors, which can make the "feels-like" temperatures a lot hotter than the actual air temperature.
Generally, the criteria for heat alerts vary by local NWS offices and are based, in part, on the air temperature and heat index values.
HOW THE WEATHER YOU’RE ACCUSTOMED TO AFFECTS NATIONAL WEATHER SERVICE HEAT WARNINGS, ADVISORIES
This graphic shows the physiological effects of heat exposure at various feel-like temperatures.
(FOX Weather / FOX Weather)
Similar changes were made to alerts regarding cold weather just before the winter of 2024 as part of the NWS' Hazard Simplification Project, which is trying to make weather alerts easier for the public to understand.