An Extreme Heat Warning is in effect right now across several regions of Arizona, issued by the National Weather Service offices in Phoenix, Las Vegas, and Flagstaff. The warning covers the Northwest Valley, Aguila Valley, Parker Valley, Northwest Plateau, Marble and Glen Canyons, and Grand Canyon Country. It became active on August 5, 2026, at 11:39 a.m. MST and runs through August 9, 2026, at 8:00 p.m. MST. If you are in any of these areas during that window, this alert applies to you.
According to the National Weather Service, an Extreme Heat Warning means that a period of very hot temperatures, even by local standards, will occur. That distinction matters: this is not a routine summer advisory. The heat expected during this period exceeds what residents in these communities are already accustomed to, and the NWS is asking people to act accordingly.
What NWS Is Telling Residents to Do Right Now
The National Weather Service is directing anyone who works or spends time outdoors to take extra precautions immediately. When possible, strenuous activities should be rescheduled to early morning or evening hours, when temperatures are lower. Lightweight, loose-fitting clothing is recommended, and drinking plenty of water is essential throughout the day.
For outdoor workers specifically, the NWS guidance draws directly from the Occupational Safety and Health Administration: schedule frequent rest breaks in shaded or air-conditioned environments. This is not a suggestion to work around on busy days. Supervisors and workers alike should treat it as a firm operational protocol for the duration of this warning.
Knowing the signs of heat exhaustion and heat stroke is a core part of the NWS instruction for this event. Heat exhaustion can include heavy sweating, weakness, and nausea. Heat stroke is a medical emergency. If someone stops sweating, becomes confused, or loses consciousness in the heat, call 911 immediately. Anyone overcome by heat should be moved to a cool, shaded location right away while emergency services are contacted. Do not wait to see if the person recovers on their own.
Public cooling shelters are available in some areas covered by this warning. The NWS advises consulting county officials directly for locations and hours. If you do not have reliable air conditioning at home, identifying the nearest cooling shelter before you need it is a practical step to take now, while conditions are still manageable.
Connecting This Alert to Longer-Term Preparedness
Extreme heat is consistently one of the deadliest weather hazards in the United States, and events like this one are a useful prompt to review your household’s heat response plan before the next warning cycle arrives. At usriskradar.com, our evergreen guidance on heat preparedness covers how to build a simple cooling kit, how to check on neighbors who may not have air conditioning, and how to identify early warning signs in children and older adults. The preparations that protect a household during a five-day warning in August are the same ones that matter during an unexpected heat event in May or September. Use the time this warning is in effect to put those basics in place.
For the latest updates on this Extreme Heat Warning, monitor the National Weather Service at weather.gov and follow guidance from Maricopa County, Mohave County, and Coconino County officials for shelter locations and local resources.
For the fundamentals that apply beyond this specific alert, see our Extreme Heat Preparedness guide.
Source: National Weather Service (NWS Phoenix AZ, NWS Las Vegas NV, NWS Flagstaff AZ). Active alert data retrieved 2026-08-05 22:00 UTC via api.weather.gov.
