An extreme heat warning is a notice issued by the National Weather Service of the United States within 12 hours of the heat index reaching one of two criteria levels. In most areas, a warning will be issued if there is a heat index of at least 105 °F (41 °C) for more than three hours per day for two consecutive days, or if the heat index is greater than 115 °F (46 °C) for any period of time.[1]
Extreme heat can pose a threat to human life and other animals, through conditions such as heat stroke, heat exhaustion, dehydration, and other heat-related illnesses.[1]
On March 10, 2025, the National Weather Service updated the Excessive Heat Warning and Watch, and renamed it to the Extreme Heat Warning and Watch, based on a public survey results in 2018.[2]
- ^ a b National Weather Service. "Excessive Heat Warning". Glossary - National Weather Service. Retrieved 17 June 2024.
- ^ https://www.weather.gov/media/notification/pdf_2023_24/scn24-88_heat_haz_simp.pdf