Adapting to extreme heat takes more than changing the clock
Add Axios as your preferred source to
see more of our stories on Google.
Workers install a fire hydrant in Quincy, Massachusetts, on May 19, when nearby Boston hit a record-high 96°F. Photo: David L. Ryan/The Boston Globe via Getty Images
As extreme heat makes afternoons more dangerous, schools, sports teams and outdoor employers are shifting when — and sometimes whether — people can safely be outside.
Why it matters: Adapting to hotter conditions could reshape the American workday while putting a premium on the cooling and energy infrastructure people rely on when outdoor conditions become unsafe.
State of play: The federal Occupational Safety and Health Administration recommends that employers facing dangerous heat consider moving work to early morning or late afternoon, shortening shifts, rotating workers and reducing strenuous work during the hottest parts of the day.
- California's new Extreme Heat Action Plan links protecting heat-vulnerable groups, including workers, with expanding access to indoor cooling and strengthening energy systems to reduce grid strain and outages.
- Oregon's statewide heat-illness prevention rule kicks in when the heat index reaches 80°F, requiring water, shade and acclimatization, with additional measures such as preventive cooldown rest breaks at 90°F, Oregon OSHA told Axios.
By the numbers: Oregon OSHA conducted 3,104 inspections addressing heat and issued 408 citations totaling $652,640 in initial penalties from 2022 to 2025, according to data shared with Axios.
Case in point: Texas offers a glimpse of the practical tradeoffs that come with reorganizing daily life around heat.
- Under new statewide rules, schools are moving sports practices to very early or late hours when conditions become dangerous. "Many of our schools have directly adapted their practice times," University Interscholastic League (UIL) athletic director Ray Zepeda told Axios.
- Moving practices away from peak heat reduces coaches' exposure, Zepeda said, but stretches the workday for coaches and athletic staff who are full-time school employees. "It is increasing their workday," Zepeda said.
Reality check: Shifting schedules isn't always enough. Cooling is becoming more important for heat safety at the same time extreme heat can stress the electricity system powering it.
- "Heat can also stress our electricity grid," California Natural Resources science adviser Andrew Jones said during a recent discussion of the state's updated Extreme Heat Action Plan.
- A grid failure during a heat event is especially concerning because people rely on electricity for air conditioning and safe indoor spaces, he said.
Between the lines: During strenuous outdoor work, workers' own metabolism can become a major source of body heat, Jennifer Vanos, an associate professor at Arizona State University who studies extreme heat and human health, told Axios. Research published this year found rest and self-pacing can help workers manage heat stress.
- Reducing work intensity or spending less time working can lower heat load, but both can mean less work gets done in that period. "No matter what, somebody is going to pay the price," Vanos said.
- Vanos points to research suggesting adequate rest and cooling can help workers remain productive while staying safer in hot conditions.
The big picture: Changes to working hours are already part of adapting to extreme heat in places like Phoenix, where Vanos said it's "pretty dead" outside during the day.
- "Part of the shift to being able to live and play and work in these hotter conditions will be having to have certain schedule changes so that everybody can be safer," Vanos said.
- Overnight heat can also limit how far schedules can shift. Climate change and the urban heat-island effect can keep nighttime temperatures elevated, and in Phoenix "we're reaching some of those limits overnight" for hard physical work, Vanos said.
The bottom line: Shifting the clock can buy people relief from extreme heat — but as the number of dangerously hot hours grows, there may be fewer safe hours to shift into.
