As a heat dome bakes much of the United States and wildfire smoke compounds air quality concerns across the Midwest and Northeast, pediatricians and public health officials are urgently reminding caregivers that infants and young children face heat risks that are fundamentally different from and more severe than those faced by older children and adults. Babies and toddlers cannot regulate their body temperature effectively, cannot ask for water, cannot recognize when they are overheating, and depend entirely on the adults around them to notice danger and respond.
The consequences of missed signals are severe. In 2025, 31 children died of heat stroke after being left in hot vehicles, according to the National Highway Traffic Safety Administration, as reported by the Associated Press. Heat stroke in infants can develop within minutes when environmental conditions turn dangerous, and it can be fatal before symptoms are obvious to a distracted caregiver.
Why This Matters
The physiological reasons infants and young children are more vulnerable than adults are specific and well-documented. Infants have a higher ratio of body surface area to body mass than adults, which means they absorb heat faster from the surrounding environment relative to their size, according to the EPA's guidance on protecting children from extreme heat. They produce more heat per unit of body weight during physical activity (including the simple act of crying). Their immature sweating mechanisms are less effective at dissipating heat than an adult's, making it harder for them to cool themselves. And they cannot seek shade, remove clothing, drink water, or otherwise self-protect.
The combination of an active heat dome and wildfire smoke in parts of the country adds an additional layer of complexity. PM2.5 from wildfire smoke irritates the airways and worsens respiratory distress at the same time that heat stress is already placing demands on a baby's cardiovascular system. For infants with any respiratory condition, including RSV-related lung vulnerability or reactive airway disease, the dual threat of heat and smoke is more dangerous than either alone.
"Infants, toddlers and young children need outdoor activity to build strong bodies and minds, but they also require extra care in the heat," said Dr. Meg Langlois, a pediatrician, according to the Associated Press. She noted that caregivers should limit the time infants and toddlers spend outside in hot weather without preventing all outdoor activity, because children need movement and stimulation even in summer months.
What We Know So Far
The American Academy of Pediatrics (AAP) provides specific guidance on pediatric heat protection that addresses the age-specific risks faced by infants and toddlers. High temperatures and extreme heat can cause children to become ill very quickly, leading to dehydration, heat cramps, heat exhaustion, and heat stroke. Heat stroke is classified as a medical emergency.
The EPA specifically flags that children absorb heat faster, lose more fluid quickly, and may lack the judgment to recognize overheating or limit exertion during hot weather, especially toddlers, who are highly motivated to keep playing regardless of how they feel. Older children may push through discomfort; infants simply do not show early warning signs the way an adult would before conditions become dangerous.
The current heat dome has affected much of the continental United States for several days, pushing heat indices above 100 degrees F in many regions. For infants in these conditions, even indoor environments without air conditioning can become dangerous if ventilation is poor and temperatures rise.
Where the Risk Is Highest
Any environment where an infant or toddler is exposed to high temperatures without adequate cooling, shade, hydration, and adult supervision creates risk. The specific scenarios the CDC and AAP flag as highest-risk include:
Hot vehicles. Car temperatures can rise 20 to 30 degrees above outside air temperature in as little as ten minutes, even when windows are cracked. On a 90-degree day, the interior of a car can reach 130 to 170 degrees within 30 to 45 minutes. This is the most common cause of heat-related pediatric death in the United States. 31 children died this way in 2025 alone. Never leave an infant in a vehicle unattended, even briefly.
Homes and daycare settings without air conditioning. Not every American household has functional air conditioning. During a heat dome, indoor temperatures in un-air-conditioned spaces can rise to dangerous levels for infants even without direct sun exposure.
Outdoor settings during peak heat hours. The American Academy of Pediatrics advises avoiding outdoor activities during peak heat (10 AM to 4 PM) when possible.
Areas affected by both heat and wildfire smoke. In states currently under both heat warnings and air quality alerts, including parts of Michigan, Ohio, New York, and other states in the Northeast and Midwest, the combination of high temperatures and elevated PM2.5 creates compounding respiratory and cardiovascular stress, particularly for infants with any underlying health condition.
What Doctors and Experts Say
The AAP describes the signs of heat-related illness in children as progressing from dehydration (fussiness, less urination, dry mouth) through heat exhaustion (faintness, extreme tiredness, headache, nausea, and profuse sweating) to heat stroke (very high temperature, confusion, loss of consciousness, and cessation of sweating as the cooling mechanism fails). Heat stroke in a child is a 911 emergency with no exceptions.
Breastfed infants and bottle-fed infants may need additional fluid during extreme heat events, though the AAP notes that exclusively breastfed infants under six months generally do not need supplemental water; nursing more frequently provides both nutrition and hydration. Caregivers of formula-fed infants should ensure that formula is being prepared correctly and not concentrated, and that infants are feeding adequately and producing wet diapers at normal frequency.
The EPA notes that children with chronic conditions, including heart or lung disease, developmental delays, or immune conditions, face compounded risk during heat events and should be monitored particularly closely.
Symptoms and Warning Signs to Watch For
For infants (under 12 months) and toddlers (1–3 years), watch for these heat-related warning signs:
Early dehydration and heat stress signs:
- Fewer wet diapers than normal (less than six in 24 hours for infants is concerning)
- Dry or sticky mouth
- No tears when crying
- Unusual fussiness or lethargy
- Sunken soft spot (fontanelle) on infant's head
- Skin that looks flushed, dry, or pale
Heat exhaustion signs requiring immediate cooling and medical contact:
- Extreme lethargy or weakness
- Nausea or vomiting
- Rapid heartbeat or rapid breathing
- Excessive sweating
- Unusual paleness or coolness of skin despite warm environment
- Loss of interest in eating or drinking
Heat stroke signs requiring 911 immediately:
- Body temperature at or above 104 degrees F (40 degrees C)
- Confusion, unresponsiveness, or loss of consciousness
- Stopping sweating despite continued heat (the cooling system has failed)
- Seizures
- Rapid, strong heartbeat
- Hot, red, dry, or damp skin
If heat stroke is suspected in an infant or toddler, call 911 immediately and begin cooling by moving the child to air conditioning, applying cool (not ice cold) water to the skin, fanning, and removing clothing while waiting for emergency services. Do not give fluids by mouth to a child who is losing consciousness.
What You Can Do Now
- Never leave an infant or young child in a parked vehicle, even for one minute. Lock your car when not in use to prevent children from climbing in unsupervised.
- During peak heat hours (10 AM to 4 PM), keep infants and toddlers indoors in a cool environment. Close blinds and curtains to block solar heat gain.
- Run fans or air conditioning. If your home lacks air conditioning, identify your nearest cooling center (contact your city or call 211) and plan to go there during the hottest part of the day.
- Dress infants and toddlers in lightweight, light-colored, breathable clothing. Remove excess layers.
- Increase feeding frequency. Breastfed infants should nurse more often. Formula-fed infants should receive adequate, correctly prepared formula. Children eating solid foods can have extra fluid-rich foods.
- Monitor wet diapers as a hydration proxy. Fewer than normal wet diapers is an early warning sign of dehydration.
- In areas under both heat warnings and air quality alerts from wildfire smoke, keep infants and toddlers indoors with windows closed. If your home is not air-conditioned and indoor temperatures are dangerously high, prioritize going to a cooling center even if outdoor air quality is poor, as heat stroke risk may exceed the smoke exposure risk in extreme cases.
- Place a reminder on your car's back seat, driver's seat, or set a phone reminder whenever you have an infant in the vehicle, to ensure the child is not inadvertently left behind.
- If you are the caregiver of a child with a chronic health condition, contact the child's pediatrician for condition-specific heat guidance.
Cost and Access: What Patients Should Know
Cooling centers are typically free and operated by local governments during heat emergencies. To find your nearest cooling center, call 211 (available in most U.S. metro areas) or contact your local city or county health department. Many public libraries, community centers, and cooling halls are open extended hours during heat events.
For families without access to air conditioning who cannot reach a cooling center, a cool bath or shower for the child provides temporary heat relief. Wet towels on the back of the neck and wrists can also help. Ensure infants are never left in a bath or pool unattended.
The AAP's HealthyChildren.org maintains free, up-to-date guidance on protecting children during heat events, including condition-specific guidance for children with asthma, heart conditions, and other chronic diseases.
What Happens Next
The current heat dome is expected to shift as weather patterns change, but extreme heat events are projected to become more frequent and more severe in the coming years due to climate change, according to the EPA and NOAA. The pediatric heat safety guidance from the AAP and CDC will remain current and applicable whenever high-temperature conditions emerge in any part of the country. MedicalDaily will update coverage as heat conditions change and when new guidance from the AAP or CDC is issued.
The Bottom Line
Infants and toddlers face heat risks that are uniquely severe: they absorb heat faster, sweat less effectively, cannot communicate distress, and depend entirely on caregivers to keep them safe. During the current heat dome, the most important immediate protective actions are never leaving an infant in a vehicle, keeping young children in cool environments during peak heat hours, maintaining hydration, monitoring wet diapers, and knowing the warning signs of heat exhaustion and heat stroke that require immediate emergency response. If a child is in heat stroke, call 911 immediately and begin cooling while waiting for help.
