How Hot is Too Hot For Baby

What degree of heat is dangerous for a baby to be exposed to outside? If the heat index is higher than 90 degrees Fahrenheit, the American Academy of Pediatrics (AAP) advises parents not to take their babies outside for extended periods of time. Babies can quickly become overheated if they are left outside for an extended period of time on days that are extremely hot.

How warm is too warm for the room where you keep your baby? To give you the short answer, any temperature that is higher than 21 degrees Celsius. Temperatures between 18 and 21 degrees Fahrenheit are ideal for the restful sleep of infants. Dressing them in one more layer than you feel is necessary for you to sleep comfortably is a good rule of thumb to follow in order to keep them warm.

It is imperative that your child not overheat at any point. If your infant is too hot, they are likely to be uncomfortable, they may have trouble sleeping, and they may develop a heat rash. The risk of sudden infant death syndrome (SIDS), also known as infant overheating death, can be increased when temperatures are excessively high.

Studies have shown that the risk of sudden infant death syndrome (SIDS) is increased by wearing bulky clothing, an excessive number of layers, and keeping the room temperature high. The winter months pose a greater threat of sudden infant death syndrome (SIDS) to infants, which may appear to defy logic. The reason for this is that parents are afraid their child will catch a cold, so they try to protect them from it by dressing their child in too many layers or turning up the thermostat.

Why Babies Overheat Easily

Young children have a difficult time controlling their internal temperature. To begin, their core temperature rises considerably more rapidly than yours does. In addition, babies and children sweat less than adults, which makes it significantly more difficult for them to cool down. And it’s not just that infants have a higher risk of overheating; they also have a higher risk of contracting an illness that’s brought on by the heat. For example, because infants’ sweat glands aren’t fully developed, they are more prone to developing heat rash or prickly heat than older children and adults.

Normal Infant Temperature

Babies typically have a temperature of about 97.5 degrees Fahrenheit when they are healthy (36.4 degrees Celsius). Temperatures of 100.4 degrees Fahrenheit or higher (38 degrees Celsius or higher) are associated with overheating and fevers in infants. It is important to keep in mind that your baby’s normal baby body temperature can change throughout the day.

Signs of a Baby Overheating

There is, fortunately, a quick and simple method for determining whether or not your child is overheated. Feel their ears and neck with your fingers. If your baby’s ears are red and hot, and their neck is sweating, then they are experiencing too much heat. Dress them more lightly, or turn down the temperature in the room.

Is your baby overheating? How to check…

Below you’ll find a few signs and symptoms of a baby overheating:

  • Warm to the touch
  • Red skin
  • Rapid heartbeat
  • Fever without sweating
  • Lethargic or unresponsive
  • Vomiting
  • Dizzy or confused

Ideal Baby Room Temperature

No matter the season, keep the room your baby is in between 68 to 72 degrees Fahrenheit (20 to 22.2 degrees Celsius). While you can measure the room temperature with a thermometer, in general, the temperature should not be too cool or too warm for an adult

How to Prevent Overheating During Sleep

In addition to setting the thermostat to the ideal sleeping temperature, avoid over-bundling your little bundle for naps or at bedtime with extra layers of clothing or hats. Here are some pointers on dressing your little one for sleep:

  • DON’T use a hat for sleep. Hats are especially problematic because covering their head reduces your baby’s ability to use their head as a little radiator, giving off extra heat. Also, in the middle of the night, a hat might accidentally slip over your little one’s face and cause breathing difficulties.
  • DO wrap Baby in a lightweight swaddle. In hot weather, it’s fine to let your baby sleep in just a short-sleeve bodysuit and light muslin swaddle. (My Sleepea 5-Second Swaddle is made from organic cotton and features breathable mesh at shoulders and legs to further reduce risky overheating.) In cooler weather, opt for a long-sleeve bodysuit or footie pajamas and a swaddle. (For babies who are rolling, swap the swaddle for a lightweight sleep sack.)
  • DON’T use loose blankets. Never use loose blankets, which are an overheating risk and a suffocation risk. (A safe crib is a crib free of toys, blankets, and all objects except a pacifier.)
  • DON’T use electric blankets (or heating pads) with your baby. These overheat infants and expose them to electromagnetic radiation.
  • DO place Baby’s bassinet away from the heater. Keep your little one a good distance away from heating vents, radiators, portable heaters, and fireplaces to avoid overheating.

How to Prevent Overheating in the Winter

Bundling babies for cold-weather adventures—plus cranking the indoor heat—can easily increase their risk of overheating. Not only are babies terrible at regulating their body temperature, they lack enough body fat to keep themselves insulated and snug. Plus, newborns have yet to develop the shiver reflex, which works to increase body heat in the cold. Here are common-sense steps to avoid your baby overheating in the winter:

  • DO dress Baby in layers. Dress your little one in one more layer than you’re wearing. If your bub gets too warm, simply peel off a layer. For outdoors, start with a long-sleeve cotton bodysuit, then add soft pants, socks, and a sweater. If you’ve got a jacket on, your baby should have a jacket or snowsuit on, too—plus a blanket. Finally, don’t forget a hat, mittens, and warm booties to keep their head, hands, and feet warm
  • DON’T dress your baby in a sweater when using a baby carrier. If you’re wearing a baby carrier, your baby likely doesn’t need a sweater or sweatshirt under their jacket. That’s because your body heat will provide just enough extra warmth to keep your little one toasty, without overheating. (Make sure your little one’s face isn’t pressed against your chest or clothing!)
  • DO use a blanket instead of a coat in the car. Bulky coats and snowsuits should not be worn in the car seat. They leave too much space under the harness, endangering your baby in the event of a car accident. Instead, secure your little one into their car seat jacket-free, then place a blanket on the lower part of their body. Once the car warms up, remove the blanket.

How to Prevent Overheating in The Summer

It’s no surprise that high outdoor temperatures put babies and children at an elevated risk for becoming overheated. Here are some easy to-dos to keep your little one from overheating in the summer:

  • DON’T go out during peak heat. The day is always at its hottest between around 10am and 2pm. Try to avoid extended outside time during those hours when the temperature is high. And spend time in the shade otherwise!
  • DO seek air conditioning. If you don’t have air conditioning at home and you’re experiencing extreme heat, find a nearby building that has AC, like the library or shopping mall. And if you do have AC, never put your baby to sleep next to the unit or they’ll get too cold.
  • DON’T cover the stroller. Draping your baby’s stroller with a muslin blanket may shield your bub from the sun, but it traps heat, increasing the temperature of the stroller…and your baby. Instead, use a large canopy or mesh sun shield specially designed for strollers that provide shade and adequate airflow.
  • DO keep hydrated. Babies get all their hydration needs from either breastmilk or formula, so on steamy days, offer more of the same. But you should not give your baby water in the first 6 months of life. From 6 to 12 months, however, 4 to 8 ounces a day is okay.

How to Cool Down an Overheated Baby

If you believe your baby is overheating, then here are some steps that you can try to cool down your little one:

  • Offer your baby fluids. If younger than 6 months, offer breastmilk or formula only. If between 6 months and 1 year, offer 4 to 8 ounces of water a day.
  • Take your baby to a cooler room. Know that lower floors—and shaded rooms—will be cooler.
  • Dress your baby in light clothing. Cotton and breathable loose-fitting fabrics are ideal.
  • Sponge your baby in lukewarm/cooler water. Don’t use cold water or ice in the bath.
  • Apply a cold compress. Hold it to your baby’s forehead or limbs to help cool them down.

If symptoms do not improve, contact your pediatrician.

Baby Overheating & Heat Rash

Heat rash, also known as prickly heat, is a skin condition that affects infants and occurs when the skin is irritated by sweat that has become trapped under the clothing. It will show up on your infant’s neck, armpits, chest, back, elbows, or thighs the vast majority of the time. A fever, chills, and bumpy skin may accompany the rash that appears as tiny red dots (irritated hair follicles) and splotchy patches on the skin. Heat rash will typically clear up on its own within two to three days in the vast majority of cases. However, if you suspect that your child has a heat rash, you should still call your child’s doctor. For the purpose of absorbing excess sweat and preventing irritation, they might suggest that you dust yourself with cornstarch powder rather than talcum powder. A cool compress applied to the heat rash and cool baths given to your infant can also be helpful in treating the heat rash.

Newborn Overheating vs. Fever

It’s natural to think that your overheated baby may have a fever. To be sure, take your baby’s temperature and consult your healthcare provider if you have any concern. (For the most accurate temperature reading in babies and toddlers up to 3 years old, use a rectal thermometer.) Additionally, the symptoms below indicate that your baby may have a fever:

  • Difficulty sleeping
  • Lack of eating
  • No interest in playtime
  • Lethargic or not as active as usual

Any baby under 3 months with a rectal temperature of 100.4 degrees Fahrenheit or higher, must be checked by a doctor. And any child with a fever over 104 degrees Fahrenheit needs to be evaluated. So, if you see those numbers, don’t hesitate to give your pediatrician a call!

Baby Overheating: Final Thoughts

The thing to keep in mind is that babies cannot regulate their body temperature well, so you always want to avoid extremes in temperature, whether that’s hot or cold. If you’re ever not sure if your baby is too hot, do the “ear check” to be safe!

Baby Too Hot Symptoms

How hot is too hot for your baby’s bedroom? Here’s the short answer: anything above 21 degrees celsius.  Babies are most comfortable sleeping between 18 and 21 degrees.  The rule of thumb to keep them warm is to dress them in one more layer than you feel you need to sleep comfortably. 

But what to do in the summer with no air conditioning?

Therein lies the need for the long answer.

One thing is certain: it is safer for baby to be too cold than too hot. Babies will wake and cry if they’re a bit chilly, and you can solve the problem then. But they won’t likely do the same if they’re too hot. And while I don’t like to spark fear, especially when the summertime heat is beyond our control, overheating is a risk factor for SIDS (sudden infant death syndrome). 

If you’re one of those parents whose home is just stifling and you can’t seem to cool baby’s room, here are some ideas and tips to help keep your baby safe and comfortable:

  • Dress baby as lightly as possible (see rule of thumb in the first paragraph). Sometimes this could mean nothing but a diaper or just a light, sleeveless sleep sack.
  • Keep a fan running on high in the room in the hours before bedtime. Turn it to low, direct it away from your baby and keep it far from his reach before you put baby down.
  • Remove any waterproof mattress coverings while the weather is hot as it doesn’t breathe as well.
  • Invest in good window coverings for baby’s room and keep them closed all day with the windows open to prevent the sun from heating the room more.
  • If your baby falls asleep in the stroller, keep a close eye as she can easily get too warm in there. And don’t cover the stroller with a blanket – this can trap more heat inside.
  • If your baby falls asleep in her carseat, keep the car running and air conditioning on. I know, I know, more greenhouse gasses, more climate change and more hot temperatures. But you have a pretty good reason; all those other idlers should get with the program. (And car seats are for cars – don’t let baby sleep in the car seat at home.)
  • Here’s a great idea from Babycenter UK’s web site: hang wet towels over chairs and window frames (never over baby’s crib railings!) as the evaporating water can cool the air.
  • Give your baby a cool bath before bed.

If you think your baby may be too hot, feel his belly; if it feels overly warm or he’s sweaty, remove a layer; it’s worth waking him for.  Remember that it’s normal for your baby’s hands and feet to be cooler than the rest of his body, so don’t check there.

While we move through the lazy (or busy!) months of summer, don’t forget to keep yourself and your baby well hydrated. For babies under 6 months, breastfeeding to meet demand should be sufficient; just be sure she’s having a normal number of wet diapers. If your baby is a little older, offer water from a sippy cup more often than usual. 


Giving your baby a cool bath before bedtime can help keep him cool for sleep in warm temperatures.
Giving your baby a cool bath before bedtime can help keep him cool for sleep in warm temperatures.

More on Baby Safety:


Dr. Harvey Karp, one of America’s most trusted paediatricians, is the founder of Happiest Baby and the inventor of the groundbreaking SNOO Smart Sleeper. After years of treating patients in Los Angeles, Dr. Karp vaulted to global prominence with the release of the bestselling Happiest Baby on the Block and Happiest Toddler on the Block. His celebrated books and videos have since become standard pediatric practice, translated into more than 20 languages and have helped millions of parents. Dr. Karp’s landmark methods, including the 5 S’s for soothing babies, guide parents to understand and nurture their children and relieve stressful issues, like new-parent exhaustion, infant crying, and toddler tantrums.

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