Extreme Heat Toolkit

The Climate and Health Program’s Extreme Heat Toolkit can serve as a critical resource for local governments, health departments, and communities to prepare for and respond to extreme heat events in Wisconsin. It includes:

• Background information and definitions of extreme heat in Wisconsin.
• Practical guidance and strategies for the health impacts of heat.
• News releases for media and talking points related to heat.
• Other useful heat reference materials.

These resources can be adapted and distributed as needed.

Recognizing heat illness and symptoms

Heat illness is no joke. Recognizing heat illness and its symptoms in those around us helps to keep each other safe. Certain groups in our communities are at a higher risk of heat illness than others, particularly:

• Older adults
• Younger children
• People living alone or without shelter
• Non-English speakers
• Outdoor workers
• People with chronic health conditions
• Athletes
• People without reliable air conditioning

A few ways that heat illness can present itself are as rashes, cramps, stress, edema, exhaustion, and stroke. An elevated body temperature (up to 104°F) is a shared symptom of most cases of heat illness that may lead to heat stroke if left unattended.

Heat rash is caused by excessive sweating that blocks sweat ducts. Symptoms range from a red rash or cluster of pimples, blisters, or itching.

Heat cramps are muscle spasms caused by dehydration or electrolyte deficiency, often in the abdomen, calves, thighs, or shoulders.

Heat stress makes it hard for your body to cool down, causing heat illness. Symptoms include hyperventilation and muscle spasm, tingling, or numbness.

Heat edema is swelling from heat exposure that causes blood vessels to expand, particularly in the ankles, feet, and hands of older adults.

Heat exhaustion is the body’s response to excessive salt and water loss through sweating. Symptoms include muscle cramps, profuse sweating and weakness, rapid breathing, dizziness, nausea, or vomiting.

Heat stroke is a life-threatening form of heat illness from an accumulation of other symptoms related to excess heat exposure. Seek medical attention immediately! Symptoms include an oral body temperature ≥104°F, loss of consciousness, confusion, rapid pulse, hot/red/dry skin, headache, dizziness, nausea, or vomiting.

If someone is experiencing any of these symptoms during an extreme heat event, you should:

• Remove the affected person from heat.
• Find a cool location to rest (call 211 or visit 211.org to find a community cooling center near you).
• Have them drink fluids with plenty of electrolytes.
• Seek medical attention if symptoms don’t improve.

“Super” El Niño and 2026’s summer weather — how will it impact Wisconsin?

For those paying attention to weather trends, the new term “super El Niño” has been everywhere. An “El Niño” is a natural climate pattern of rising surface water temperatures (usually 0.5 - 1.0°C) in the Pacific Ocean, which in turn affects global weather patterns —yes, including Wisconsin! Make it “super” (more than 2.0°C warmer), and you have a recipe for more intense weather effects worldwide. We chatted with Andy Boxell at the National Weather Service to ask if this weather phenomenon will impact summer heat.

“El Niño impacts are pretty muted during the summer,” Andy said. “The effects tend to be much more pronounced during the winter months, usually with warmer and drier conditions.”

The Climate Prediction Center outlook shows near-average conditions for the upcoming summer. But that doesn’t mean we should slow down on our heat preparedness. Create a heat response plan for your community and encourage folks to stay hydrated and seek cool spaces as the temperature rises. Interested in creating a heat response plan? Contact the Climate and Health Program at DHSClimate@dhs.wisconsin.gov for support.

Mosquito season has officially begun

This year, we’ll be paying particularly close attention to the Culex mosquito, carrier of the West Nile virus, which is the most common mosquito-borne disease in the continental United States. 

Wisconsin reported over 27 cases of West Nile last year and 25 hospitalizations across 26 counties. The risk of West Nile virus and other mosquito-borne illnesses peaks in late summer, but infections can occur any time mosquitoes are active. You can track West Nile cases on the Wisconsin DHS website. The Bureau of Communicable Diseases has a great factsheet on the illnesses spread by mosquitos, the symptoms, treatment options, and prevention.