Climate Connect: Summer is heating up – stay cool, Missoula!
Susan Teitelman
Heat dome summer has arrived, as evidenced by three scorching heat waves in Europe and severe heat alerts in more than half the states across the U.S. This is our new normal.
Heat domes, which scientists warn will become more frequent and intense with climate change, occur when high pressure systems trap and heat up the air beneath it – like a lid on a pot holding in steam. Heat domes can persist over days or weeks and can stretch over hundreds of miles.
The heat domes in Europe this year have broken numerous
Here in the United States,160 million people in 30 states were under an alert for extreme temperatures last week, prompting event cancellations, spiking heat-related emergency room visits, and straining electrical grids. The U.S. Department of Energy declared an emergency, directing the largest electrical grid company to take measures to prevent blackouts and safeguard essential functions like hospital operations.
In our neck of the woods, things are also heating up, with Missoula temperatures set to soar into the 90s this weekend and next week. Heat is on the rise across the world, and Missoula is not immune to this development. Extreme heat is one of the top five extreme weather hazards in Missoula County, and across the county the increase in the number of annual days above 90 degrees is a trend that is expected to continue as a result of climate change.
Extreme heat is dangerous – it’s the number one weather-related killer nationwide. But, these deaths are preventable with proper planning and action.
To address the threats posed by extreme heat, our community launched the Stay Cool Missoula initiative in 2023, spearheaded by Missoula
Last summer, our Stay Cool team organized and executed Heat Watch – a countywide heat mapping project – to understand heat distribution across Missoula County and help our local communities and residents plan and prepare for rising temperatures coming our way.
Heat Watch, the first of its kind in Montana, was held on August 12th, 2025, and was coordinated by our Stay Cool Missoula team and partners from the Center for Collaborative Heat Monitoring, CAPA Strategies, and the Oregon Museum of Science and Industry. More than 30 local citizen science volunteers collected data on the hot, clear day. Using simple heat sensors mounted to vehicles, volunteers drove assigned routes three times during the day (morning, afternoon, and evening), recording nearly 76,000 air temperature and humidity measurements across 93 square miles of the county.
Among other findings, the mapping campaign confirmed temperature variability throughout the day and revealed hot spots, or urban heat islands, that exist in the county.
For example, the Westside neighborhood of Missoula, characterized by large industrial and commercial areas with impervious surfaces, exemplified a heat island. This area stayed hot throughout the day and radiated heat to warm surrounding residential neighborhoods. The Bonner and Milltown areas east of Missoula, though they’re farther from the urban core, remained warm and developed hot spots throughout the day. For comparison, the University District, which boasts a dense, mature tree canopy and lacks surrounding industrial or commercial landscapes, remained cooler than other neighborhoods.
The results of Heat Watch indicate that residents living, working, and recreating in different parts of the county have different exposures to high temperatures and hot spots. While some areas may have safe temperatures for outdoor activities, other areas may put people at risk for heat-related illnesses, especially during the warmest afternoon hours. Knowing which areas are subjected to higher temperatures can help community organizations, elected officials, and neighborhood residents, target heat mitigation efforts and help residents prepare for and respond to extreme heat.
The full results from Heat Watch are publicly available here, where you can download a summary report and explore an interactive heat map that allows users to view morning, afternoon and evening air temperature and heat index data throughout the county.
Our Stay Cool Missoula team plans to use this data to inform heat-related policies like our Extreme Heat Toolkit; the overarching community climate resilience plan Climate Ready Missoula; and other plans created by local government and community partners. We will continue to use the Heat Watch results to move forward on heat policy and action, and you can stay informed on our website.
As we experience hotter weather this summer, area residents and visitors are encouraged to visit the Stay Cool Missoula Storymap to find local resources for staying safe during heat waves. You can find our Stay Cool team tabling with information and resources at the Western Montana Fair on Wednesday, August 5th, 3:00 – 7:00pm, and at ClimateFEST at Caras Park on Saturday, September 26th, 10:00am – 2:00pm.
We’re all in this together and our team is committed to helping our community stay cool!