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In early July, wildfires erupted in Minnesota’s Superior National Forest, and forests across the border in northwestern Ontario. Normally, summers in this region are relatively wet, and fires are more likely to pop up in the drier fall or spring seasons. Summer blazes are often put out by rainfall. But this year, extreme heat combined with a worsening drought taking hold in Minnesota and the upper Midwest has been a recipe for disaster. While lightning strikes are believed to have initiated these fires, the upper Midwest’s months of hot and dry conditions have helped the fires spread quickly.
Forests and wilderness areas have closed and towns have received evacuation orders as over 1.8 million acres have burned. Thousands have been evacuated from the popular Boundary Waters Canoe Area Wilderness, as well as Canada’s adjacent Quetico Provincial Park. Canada’s First Nations communities have been particularly hard-hit, with nearly 2200 members of thirteen First Nations forced to evacuate. While catastrophic wildfires are often associated with California and other western states, the four deadliest wildfires in U.S. history have been in Wisconsin, Minnesota, and Michigan, and two of Canada’s three deadliest wildfires were in Ontario. Many future wildfire risk studies focus on western North America, with the risk for the eastern part of the continent receiving less attention. The Jupiter science team analyzed summertime temperature, precipitation, and wildfire risk in Minnesota, Wisconsin, and northwestern Ontario to understand how wildfire exposure could change in the future.
As Summers Heat Up and Dry Out, Wildfire Risk Climbs
The upper Midwest is getting hotter. Like most of North America, the upper Midwest is warming quickly, especially in the summer. Jupiter climate models predict that summertime temperatures in the upper Midwest and northwestern Ontario will warm by 3°F on average by 2050, an increase of at least 15%. Jupiter projections suggest that the hottest days of the year could be nearly 5°F hotter by 2050, and the number of days where the temperature exceeds 100°F (38°C) could increase by a factor of 4.
The upper Midwest is getting drier in the summer. While this region should see an annual increase in precipitation in a warmer world, summertime rainfall is projected to decrease. By 2050, July and August rainfall could decrease by 5 to 15% in Minnesota and northwestern Ontario. So even though the upper Midwest and northwestern Ontario are expected to get wetter overall, summers are projected to get drier; and a drier summer following a wetter spring could yield dense, young vegetation that is vulnerable to summer fires, especially in the heavily forested regions of northern Minnesota and the vast boreal forests of northwest Ontario.
Overall, wildfire risk is increasing in this region. The hotter and drier summers add up to an increase in wildfire exposure for the upper Midwest and northwestern Ontario. Jupiter projections predict a 15% increase in wildfire exposure in Minnesota, with risk higher in the heavily forested northern parts of the state. Wisconsin, which has more development and farmlands, and less forest, is predicted to see a 5% increase in wildfire exposure; and Michigan’s Upper Peninsula is projected to see a nearly 10% increase in wildfire exposure. The picture is even more grim for the heavily forested northwestern Ontario, which faces a 20 - 25% increase in fire exposure by 2050. Canada contains nearly 30% of the world’s boreal forests, and several studies suggest that wildfire risk has been underestimated in boreal forests.
No Escape: The Far-Reaching Cost of Wildfire Smoke
Even when wildfires are far away, smoke can travel thousands of miles, impacting distant communities in addition to nearby ones. Last week, the winds shifted, and many of the largest cities in the U.S. and Canada were choking on heavy smoke, leading to widespread air quality emergencies. On July 16, several midwestern cities, including Chicago, IL; Detroit, MI; Milwaukee, WI; Minnesota’s Twin Cities; and Cleveland, OH, obliterated previous records for the worst air quality on record, with peak air quality indices (AQIs) of over 500 in most of these cities, well into “Hazardous” territory. Toronto, the largest city in Canada, has had the worst air quality on Earth for much of the past week. In northeastern cities like Washington, DC; Boston, MA; New York City; Baltimore, MD; and Philadelphia, PA, July 16 approached (though did not break) all-time worst air quality records.
And the increasing heat will only make the impacts of wildfire smoke worse. Hotter temperatures exacerbate the impacts of wildfire smoke: heat speeds up the chemical reactions that create surface ozone and smog from pollutants in wildfire smoke like nitrogen oxides. While ozone high up in the atmosphere protects the Earth from ultraviolet radiation, near-surface ozone is harmful to the respiratory system, meaning that when wildfire smoke helps create additional ozone, human lungs are even more strained. Scientists estimated that wildfire smoke has actually led to an increase in ozone pollution, and in deaths due to ozone pollution, in the last decade. Beyond the direct impacts of more ozone, the hottest days are often found during high-pressure systems, where the lack of wind and rain traps the polluted air in place for days at a time, providing little relief for afflicted communities.
The health impacts of wildfire smoke have been a growing concern for wildfire scientists and public health experts; a 2025 report by the Lancet Foundation estimates that over 150,000 people died due to wildfire smoke exposure in 2024. By the end of the 21st century, this number could double. In the U.S., experts estimate that wildfire smoke could be responsible for an additional 70,000 deaths per year by 2050, a number which is nearly 3 times greater than current estimates of deaths due to wildfire smoke exposure.
The upper Midwest, with its long winters, thousands of lakes, and safety from disasters like coastal flooding and tropical cyclones, has often been described as a “climate haven”. But this region is a reminder that no region's climate profile is fixed; and that today's "climate havens" may not hold that title for long. The increasingly hot, dry summers are contributing to a substantial increase in wildfire risk in the coming years. And when it comes to wildfire smoke that can travel thousands of miles, there is no climate haven at all.
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Understanding how risk is shifting before the next fire season arrives requires forward-looking climate analytics, not just historical fire maps. Learn how Jupiter helps organizations anticipate and plan for wildfire, smoke, and other escalating climate risks. Contact us here if you want to speak with a climate expert.
