The Second Major Heat Wave in Weeks Is Breaking Records Coast to Coast

WASHINGTON D.C. — A relentless summer of extreme heat is shattering all-time temperature records from the northern Rockies to the East Coast. After highs of 111°F in Billings and 115°F in Miles City, Montana, this week's heat dome is driving heat-index values toward 110°F across the northern tier — where warnings covering more than 100 million people run through Thursday — while East Coast cities from New York to Washington could approach 100°F midweek with little relief overnight. 

Californian communities are straining under heat warnings from San Francisco to Los Angeles. It is the second major heat wave to grip the country in a matter of weeks. NRDC experts are available to discuss who is most exposed, the workers facing this heat without federal protection, and the health lifelines being weakened as the danger climbs.

Juanita Constible — extreme heat and worker safety

NRDC senior advocate for environmental health:
“Heat is the deadliest weather there is, and heat related injuries are entirely preventable. Yet millions of people will spend this week roofing, farming, and working in warehouses where the danger doesn't stop when the sun goes down, because the nights aren't cooling off either. Instead of finishing the first federal standard requiring employers to provide water, rest, and shade, OSHA spent the spring scaling back the enforcement it already had.”

The protection gap behind the forecast

Heat is the deadliest weather hazard in the United States, and there is still no enforceable federal standard requiring employers to provide water, shade, rest, or training.

• Every year, tens of thousands of U.S. workers are sickened or injured by extreme heat, and between 1992 and 2019, more than 900 workers died from heat on the job.
• The first-ever federal heat-safety standard was proposed under the prior administration, but the rulemaking stalled in 2025, and in April 2026 OSHA narrowed its heat-enforcement program rather than finalizing the rule — heading into a record-hot summer.
• The cost lands on employers too: OSHA estimates a single average case of heat exhaustion can cost more than $79,000.

What to watch

• Which states are moving enforceable workplace heat standards (NRDC's state tracker shows which do)
• The status of the stalled federal heat rule and OSHA's narrowed enforcement program as the summer's most dangerous heat arrives
• How employers and cities are responding in real time — from cooling centers to calls for employer flexibility during heat emergencies

Dr. Vijay Limaye — extreme heat, air pollution, and health resilience

NRDC senior scientist, environmental epidemiologist, and former EPA scientist:
“Almost every heat death is preventable, but only if we treat a week like this as the health emergency it is. That means cooling centers open and easy to reach, clear warnings about both the heat and the air, and communities checking on the neighbors most at risk. The heat and the smog rise together; our response has to rise with them.”

The health burden behind the forecast

• Extreme heat doesn't just cause heat stroke. It strains the heart and lungs and worsens chronic conditions like asthma, heart disease, and diabetes — and the danger compounds when nighttime temperatures stay high and the body never gets to recover, a defining feature of this week's event.
• Heat is also an air-quality emergency. Ground-level ozone — smog — forms faster in hot, sunny, stagnant air, so heat waves routinely coincide with unhealthy-air days that hit people with respiratory and heart conditions hardest.
• The people most at risk are older adults, pregnant people, those with chronic illness, outdoor workers, and low-income households without reliable air conditioning.
• These harms carry a measurable economic cost. Dr. Limaye leads NRDC's research valuing the health costs of climate change and can put a dollar figure on the toll of extreme heat.

What to watch

• Whether federal energy assistance (LIHEAP) and utility shut-off protections hold up as cooling demand peaks
• Heat-driven smog and ozone exceedances during the dome — extreme heat as an air-pollution multiplier
• Strain on health systems: heat-related ER visits and EMS calls as records fall

Available for interviews:

• Juanita Constible (Washington, D.C.) — workplace heat standards, state and federal heat policy, community heat preparedness.
• Dr. Vijay Limaye (Madison, WI) — climate-health science, air quality, heat-health burden, climate adaptation and resilience.