Phoenix summers are deadly serious. With temperatures routinely exceeding 110°F, heat illness is one of the leading causes of weather-related fatalities in Arizona — and it’s entirely preventable. Here’s what you need to know.
No city in America experiences heat the way Phoenix does. With over 110 days per year above 100°F and record temperatures that have topped 118°F, the Phoenix metro area consistently ranks among the hottest urban environments on earth. The combination of intense solar radiation, urban heat island effects from miles of asphalt and concrete, and increasingly warm overnight lows creates conditions that can be life-threatening for workers, the elderly, the homeless, and anyone without access to reliable cooling.
According to Maricopa County public health data, heat-related deaths in the Phoenix metro area have increased significantly over the past decade. In a single recent summer, more than 400 heat-associated deaths were recorded in Maricopa County alone — a sobering reminder that this is not just a matter of discomfort. Heat is a public health emergency in Phoenix, and protecting yourself and your community requires knowledge and preparation.
⚠️ Know the Warning Signs of Heat Illness
- Heavy sweating
- Cool, pale, clammy skin
- Fast, weak pulse
- Nausea or vomiting
- Muscle cramps, tiredness, weakness
- High body temperature (103°F+)
- Hot, red, dry or damp skin
- Rapid, strong pulse
- Confusion or loss of consciousness
- Throbbing headache
- Hydrate aggressively. Drink water every 15–20 minutes during outdoor activity — don’t wait until you’re thirsty. Avoid alcohol and excessive caffeine in the heat.
- Seek shade and schedule wisely. Outdoor work and exercise should be done in early morning or after sunset whenever possible. Rest in shade frequently during midday hours.
- Wear appropriate clothing. Light-colored, loose-fitting, breathable fabrics help your body manage heat. UV-protective hats are essential for outdoor workers.
- Never leave people or pets in vehicles. Car interiors in Phoenix can exceed 160°F within minutes on a hot day. This is fatal.
- Check on vulnerable neighbors. The elderly, very young children, and individuals experiencing homelessness are at extreme risk during heat events. Phoenix operates designated cooling centers — know where they are.
- Employers: Follow ADOSH heat rules. Arizona law requires employers with outdoor workers to provide water, shade, and rest breaks when the heat index reaches dangerous levels.
Phoenix’s Maricopa County operates a network of cooling centers throughout the summer months — libraries, community centers, and designated shelters that provide free air-conditioned respite for anyone who needs it. InSource Safety maintains an updated list of cooling center locations for the Phoenix metro area. Community members are encouraged to share this resource widely, especially during excessive heat warnings issued by the National Weather Service.
Preparation saves lives. Whether you’re an employer with an outdoor workforce, a neighbor checking on an elderly resident, or an individual planning outdoor activities, understanding Phoenix’s heat risks and having a clear action plan is the most important safety step you can take every summer.