The National Weather Service has issued an Extreme Heat Warning — not a watch, not an outlook — for the Phoenix metro area through 8 PM MST today, May 12, 2026. High temperatures are expected to reach 110°F across much of the lower desert valley. This is an active, in-effect warning that covers a wide swath of communities across Maricopa County.
Areas under the warning include Central Phoenix, North Phoenix and Glendale, Scottsdale and Paradise Valley, the East Valley, South Mountain and Ahwatukee, the Southeast Valley and Queen Creek, Buckeye and Avondale, Deer Valley, and the Northwest Valley. If you are in any of these areas today, the NWS considers heat to be at a dangerous level through this evening.
What an Extreme Heat Warning Means
An Extreme Heat Warning is the highest-tier heat alert the National Weather Service issues. It is reserved for situations where heat poses a significant risk to human health, particularly for vulnerable populations. This is distinct from a Heat Advisory (elevated but manageable) or an Extreme Heat Watch (conditions are developing). Today’s warning means dangerous conditions are already underway and will continue through 8 PM MST.
This heat event is part of a broader pattern building across the Western U.S. A strong upper-level ridge has settled over the region, pushing temperatures well above seasonal norms from the Desert Southwest into parts of the San Joaquin Valley in California. Phoenix is experiencing the core of the most intense heat today.
Who Should Take Extra Precautions
While 110°F heat is serious for everyone, certain groups face greater risk:
Elderly residents and young children are especially vulnerable to heat-related illness. If you have elderly neighbors or family members — particularly those without reliable air conditioning — check on them today. Cooling centers are available across the valley; contact the Maricopa County Human Services Department or call 211 for locations.
Outdoor workers in construction, landscaping, delivery, and similar fields face prolonged heat exposure during the warning period. If you must work outside, take frequent shade breaks, carry and drink plenty of water, and consider a cooling towel or portable misting fan to help manage body temperature during rest periods.
Pets should not be left outside or in unventilated vehicles. Pavement and artificial turf can reach temperatures far exceeding the air temperature and can burn paws quickly. Walk dogs in the early morning before temperatures climb.
Anyone without functioning air conditioning should identify a cool location to spend the afternoon hours — a library, shopping center, or designated cooling center. The warning period runs through 8 PM MST, which means the evening will remain dangerous even as the sun drops.
Staying Hydrated
In extreme heat, thirst is a lagging indicator — you can become dehydrated before you feel thirsty. Drink water consistently throughout the day, not just when you feel parched. For anyone who will be outside for any significant period, an insulated water bottle helps keep water cold for hours, which makes it more likely you’ll actually drink enough. Adding an electrolyte drink mix to your water can help replace sodium and minerals lost through sweating — especially important for outdoor workers, athletes, and anyone spending extended time in the heat.
If You’re Going Outside
Most people in the Phoenix metro can minimize their exposure today by limiting outdoor time to early morning (before 10 AM) or after the warning expires at 8 PM MST. If you have an obligation that requires you to be outside during the afternoon — an event, a job, yard work that can’t wait — take these practical steps:
Apply a broad-spectrum sunscreen SPF 50 before going out and reapply every 90 minutes. Sunburn accelerates heat illness. A wide-brim sun hat provides shade for your face and neck, reducing heat absorption significantly. Wear lightweight, light-colored, loose-fitting clothing. Avoid alcohol and caffeine, which can contribute to dehydration.
Today’s Decision Summary
- If you must be outside between noon and 6 PM, plan for 110°F conditions. Bring more water than you think you need, take shade breaks every 15–20 minutes, and watch for signs of heat exhaustion (heavy sweating, weakness, fast pulse, dizziness).
- If you are responsible for others — a child, an elderly parent, employees working outdoors — check on them regularly and have a plan to move them to a cool environment quickly if they show any signs of heat illness.
- If you have outdoor plans this evening, note that the Extreme Heat Warning runs through 8 PM MST. Conditions remain dangerous until then, even as temperatures begin to ease.
- Tonight offers relief: lows will drop to around 85°F under mostly clear skies, which is still warm but a significant step down from the afternoon peak.
Stay Updated
This article reflects conditions as of the morning of May 12, 2026. Warnings can be updated, extended, or cancelled by the National Weather Service as conditions evolve. For the latest alerts and forecast discussion, visit the NWS Phoenix office directly:
NWS Phoenix (PSR): https://www.weather.gov/psr/ NWS Active Alerts for Arizona: https://alerts.weather.gov/
Sources: National Weather Service Phoenix (PSR), NWS Active Alerts. Forecast valid May 12, 2026.
— Weather Window Forecast Team
