Understanding the language used by the National Weather Service (NWS) during periods of extreme heat is crucial for staying safe. In March 2025, the NWS updated its heat alert terminology to improve public comprehension of the risks associated with high temperatures. These changes are designed to better communicate the urgency of taking precautions when dangerous heat is expected or occurring.

Previously, the NWS used terms like "Excessive Heat Watch" and "Excessive Heat Warning." Recognizing that these terms might not fully convey the potential danger, the agency replaced them with "Extreme Heat Watch" and "Extreme Heat Warning." This subtle but significant change aims to emphasize the severity of the situation and prompt people to take appropriate action.

So, what exactly do these alerts mean?

This is issued when conditions are favorable for extreme heat in the next 24 to 72 hours. It means that dangerous heat is possible, and you should prepare for the potential of an extreme heat event. During a watch, it's important to: Stay informed by monitoring weather forecasts and updates from the NWS. Identify cool places you can go to seek relief from the heat, such as air-conditioned libraries, shopping malls, or community centers. Ensure your air conditioning is working properly. Check on vulnerable friends, family, and neighbors who may be more susceptible to heat-related illnesses. Stock up on water and other hydrating beverages.

This is issued when extreme heat is imminent or expected to occur within the next 12 to 24 hours. An extreme heat warning indicates a high probability of dangerous heat levels that can be life-threatening. During a warning, it's crucial to: Stay indoors in an air-conditioned environment as much as possible. If you don't have air conditioning, seek shelter in a designated cooling center. Drink plenty of water and avoid sugary or alcoholic beverages. Avoid strenuous outdoor activities, especially during the hottest part of the day. Wear lightweight, light-colored, and loose-fitting clothing. Take cool showers or baths to lower your body temperature. Never leave children or pets in a parked car, even for a short period. Check on vulnerable individuals regularly.

While not as severe as a warning, a heat advisory is issued when heat index values are expected to reach levels that could cause health problems, especially for sensitive individuals. During a heat advisory: Take frequent breaks in shaded or air-conditioned environments. Drink plenty of water. Wear light-colored, loose-fitting clothing. Avoid strenuous activities during peak heat hours. Monitor yourself and others for signs of heat exhaustion or heat stroke.

The updated terminology and increased emphasis on clear communication are vital because extreme heat is a significant public health threat. It's the leading weather-related cause of death in the United States, often exceeding fatalities from floods, hurricanes, and tornadoes. By understanding the different types of heat alerts and taking appropriate precautions, individuals and communities can significantly reduce the risk of heat-related illnesses and fatalities.

Beyond understanding the alert system, there are several proactive steps you can take to protect yourself and your loved ones during periods of extreme heat: Hydrate: Drink plenty of water throughout the day, even if you don't feel thirsty. Avoid sugary drinks and alcohol, as they can dehydrate you. Stay Cool: Seek out air-conditioned environments whenever possible. If you don't have air conditioning at home, visit a cooling center, library, or shopping mall. Dress Appropriately: Wear lightweight, light-colored, and loose-fitting clothing. Limit Outdoor Activities: Avoid strenuous activities during the hottest part of the day. If you must be outside, take frequent breaks in the shade. Protect Vulnerable Individuals: Check on elderly neighbors, friends, and family members who may be more susceptible to heat-related illnesses. Never Leave Anyone in a Parked Car: Temperatures inside a parked car can rise rapidly, even on a mild day. Never leave children, pets, or vulnerable adults in a parked car, even for a few minutes.

By staying informed, taking precautions, and looking out for one another, we can all stay safe during periods of extreme heat.