The sun rises above the Mississippi River valley at the start of another warm, hazy summer day in July 2021, as seen from South St. Paul, Minn. Credit: Andrew Krueger | MPR News

Thursday’s extreme heat and humidity stormed in as a weather whiplash, jolting many Minnesotans into sudden, steamy summery conditions. Temperatures sailed into the 90s, with high humidity and a fierce, muggy wind. 

Get used to it, say meteorologists, who predict that the summer ahead will be hotter than usual across the United States, including Minnesota. 

Temperatures could average 1.8 to 3.6 degrees Fahrenheit higher through July for most of the continental United States, according to the North American Multi-Model Ensemble, a forecasting system.

And urban areas with less shade could experience much higher temperature spikes. That includes the Twin Cities metro area, which is usually about two degrees hotter than surrounding areas. And “heat islands” within the city tend to be even hotter. Areas with dark roads, lots of asphalt, parking lots and buildings trap heat. Add impermeable surfaces and less shade to the mix, and temperatures rapidly climb to create the phenomenon known as heat islands. 

A 2020 study revealed that Minneapolis’ formerly red-lined neighborhoods, areas where discriminatory housing practices took place from the 1930s through 1960s, were almost 11 degrees hotter than the city’s coolest neighborhoods. 

That means Minnesotans of color and those with lower incomes who live in those areas often suffer most from heat-related adverse health effects.

Health effects include cardiovascular and respiratory complications, preterm birth, renal failure, and kidney stones. Death rates rise during and after heat waves. People most at risk include older people, children, pregnant women. and people who work outdoors.

Last June a string of 90-degree days in Minnesota resulted in about 298 heat-related emergency room visits, about six times more than weeks in which the temperature stayed in the 70s, according to the national Centers for Disease Control and Prevention in Atlanta, Ga. 

Over the long run, finding ways to limit climate change that accelerates dangerously hot summers may help. For example, Minneapolis has responded by planting trees to increase shade, said Minneapolis Park and Recreation Board commissioner Alicia D. Smith.

“We’ve just planted upwards of 3,000 trees to expand the urban canopy,” Smith said. “It is equitable where we’re placing them and where neighbors are requesting them.”

We’ve just planted upwards of 3,000 trees to expand the urban canopy. It is equitable where we’re placing them and where neighbors are requesting them.

– Alicia D. Smith, Minneapolis Park and Recreation Board commissioner

Click here to explore what higher temperatures mean for Minneapolis.

Until shade is equitably distributed, however, lower-income people may be more likely to face multiple risk factors. If you live in a heat island and work outdoors, for example,  the health risks compound, said Audrey M. Dorélien, an assistant professor at the University of Minnesota’s Humphrey School of Public Affairs and a graduate faculty member in the university’s School of Public Health. 

“All of these things may add up,” Dorelien said. “People of different backgrounds aren’t going to be equally affected.”

Other researchers have shown that people with access to air conditioning and abundant shade react differently to heat than those without access to effective cooling.

Dorelien has studied the effects of heat on pregnant women in sub-Saharan Africa.

“They don’t have air conditioning, so they can’t adapt,” she said. “So they’re especially vulnerable. But even in a place like Minnesota, not everyone has the ability to adapt if people don’t have central air.”

A hot, humid day can cause elevated body temperatures, just as a hot tub or sauna might, she said. That can have negative consequences for both the pregnant woman and her baby. Exposure to extreme heat in the third trimester of pregnancy can trigger earlier labor, shorten gestation, and lower birth weight. One study found long-term effects in babies exposed to extreme heat in utero and in their first year after birth: Every 90 degree-plus day was associated with a .1 percent reduction in wages 30 years later. 

Hot, stagnant air can also increase air pollution, adding the stress of poor air quality to the risks faced by vulnerable groups, especially for those living with conditions such as asthma.

People who live in heat islands, including downtown St. Paul and downtown Minneapolis, and older people, youth and pregnant people should take extra precautions during heat waves this summer, Dorélien said. 

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Help is available for those at risk

While the goal – staying cool – seems simple enough, it’s not always easy. Fortunately, there are many resources to help. Smith, who also serves as executive director of Minneapolis’ Corcoran Neighborhood Association, shares these tips:

  • If you don’t have central air conditioning, check with your neighborhood organization for weatherization tips to keep your home as affordably cool as possible. Ask about money or grants for buying fans or portable air conditioning units. Neighborhood organizations can also connect you to government or nonprofit programs that can help pay for cooling systems. 
  • Ask if your neighborhood has a program to help seniors during extreme weather. The Corcoran neighborhood, for example, has a buddy check system where neighbors check on senior citizens who don’t have air conditioning. “Seniors could get forgotten, and so we say, let’s check in and see if they’re OK,” Smith said. “If it’s 90 and they can’t get to the store because they usually walk, others could bring groceries. And not only seniors, but anyone with challenging circumstances.”
  • Seek out air conditioning at places like park buildings and libraries. Libraries sometimes extend hours during extreme heat, and Smith plans to find out if park buildings could do the same. Parks and libraries are both reliable places to find water fountains, and Smith hopes parks can make water even more available, especially closer to playgrounds and basketball courts, she said. 

Symptoms of heat illness include headache, nausea, weakness, dizziness, heavy sweating or hot, dry skin, higher-than-usual body temperature and thirst. It’s serious stuff; heat illness can lead to medical emergencies.

It’s  too early to say with precision how this summer’s weather will shape up. Historically, the temperature in Minnesota reaches 90 in May about a third of the time, and the summers following tend to be hotter. But with climate change increasing the number of extremely hot days, Minnesotans can anticipate a need for more air conditioning, Dorélien said.

Last year, the warmest since 1873, Minnesotans endured 26 days of 90 degrees or higher. 

For the next week or so, though, the weather seems to be making up for the spring we missed: The forecast calls for sunny skies and high temperatures in the 60’s and 70’s. No air conditioning needed.

Sheila Mulrooney Eldred writes stories about health equity for Sahan Journal. As a freelance journalist, she has written for The New York Times, the Washington Post, FiveThirtyEight, NPR, STAT News and...