Fifteen US cities have adopted mandatory extreme heat preparedness ordinances requiring employers, schools, and event organizers to implement specific protective measures when temperatures or heat index values exceed defined danger thresholds.
Cities Leading the Way
The ordinances vary by city but share common elements addressing outdoor worker protection, public cooling access, and vulnerable population outreach.
- Phoenix, Las Vegas, Houston, Dallas, and Miami among the first adopters
- Mandatory 15-minute shade breaks every 2 hours for outdoor workers above 105°F heat index
- Public cooling centers within 1 mile of every residential area during heat emergencies
- Schools must cancel outdoor activities above 100°F heat index
- Penalties for non-compliant employers: $500-$10,000 per violation
Public Health Context
Heat-related deaths in the US exceeded 2,300 in 2025, a 40% increase over the five-year average. Public health officials describe extreme heat as the deadliest weather hazard, disproportionately affecting outdoor workers, elderly residents, and communities without adequate cooling infrastructure.
