The temperature is expected to top 100 degrees on Thursday in Riverside, Calif. In 2024, this city of roughly 323,000 residents about 50 miles from the Pacific Ocean saw 39 days above 100 degrees, a 51 percent increase from 2000, said Patricia Lock Dawson, the city’s mayor.

Extreme heat — and the numerous concerns that come with it — has become a challenge for cities across the country, as they consider resiliency strategies for a present and future impacted by climate change.

Riverside hosted the inaugural Extreme Heat Summit last September, a partnership with the National Oceanic and Atmospheric Administration (NOAA). The event served as a simulated emergency planning event with public and private entities and nonprofits.