Signs Your Baby Is Too Hot Or Cold While Sleeping

At one time or another, every parent or caregiver has stood over their baby’s cot wondering if they were too hot or too cold. Signs baby is too hot while sleeping are a little more obvious than signs baby is cold at night. In either case, there are a few things to look out for so you can ensure your baby is relaxed, comfortable and sleeping safely.

While managing your baby’s comfort temperature may not be an exact science, monitoring room temperature, choosing the right clothing and checking your baby’s body temperature are all important factors that can help you master this delicate art.

What is the best temperature for a baby at night?

A normal body temperature range for babies is between 36.5 – 38°C. It can be dangerous for babies to overheat. If your baby has a temperature over 38°C, this may indicate they are overheating or in need of medical attention.

The ideal room temperature at night for babies is between 18-22°C. See our Sleep Library for a more detailed look at creating the ideal room temperature for babies.

Why babies overheat or get cold more easily

In the early days, there is so much to learn about our little ones. Something that a lot of people may not know about babies, is that they’re not yet able to regulate their own body temperature. This is why it’s particularly important to keep a close eye on how comfortable your baby is.

Overheating for babies during sleep can be dangerous. It can cause dehydration and increases the risk of SIDS (Sudden Infant Death Syndrome).

When do babies learn to regulate their body temperature?

Babies learn how to regulate their body temperature at around 9 - 12 months. By this age your little one should begin to adapt their own body temperature to suit external conditions. Even after this stage, it’s still important to check in with your baby regularly, to ensure they are at a comfortable temperature.

How do you check a baby’s temperature?

You can check your baby’s temperature at night in a couple of ways. Either:

Feel baby’s back or stomach
Use a thermometer, either infrared or digital

The signs that your baby is too hot at night

If you’re wondering how to tell if baby is too hot at night, look out for any of the following signs:

Sweating or clammy skin
Wet hair (from sweat)
Rapid breathing
Flushed cheeks

Lethargic and not responsive
Body temperature above 38°C

How to prevent a baby from overheating

There are a few things you can do to make sure your baby doesn’t overheat:

Check your baby’s temperature at regular intervals by feeling their stomach and/or back
Look out for signs of overheating
Remove a layer of clothing
Change your baby’s sleeping bag or swaddle to a lighter thermal grade
Dress your baby according to the room temperature they’re sleeping in
Dress your baby in lightweight, breathable clothing
If your baby is traveling in a baby capsule, be careful not to overdress your baby with heavy layers (such as sweaters or coats)
Ensure your baby stays hydrated

Preventing overheating in the winter

During the cooler months it is natural to want to keep your baby warm at night. However, overheating also poses a danger to babies during winter. Here are some things you should avoid:

Do not allow your baby to go to sleep wearing a head covering, such as a beanie or bonnet

Do not use loose blankets or comforters in the cot
Never use electric blankets, heat bags, heat packs or hot water bottles for baby
Do not overheat the room your baby is sleeping in

Preventing overheating in the summer

When the thermostat is high and everyone in the house is sweating, you may be concerned about your baby overheating. To help prevent this from happening, here are some things you can do:

Ensure your baby is not overdressed, a sleeveless bodysuit underneath a lightweight swaddle may be all that is required for sleep in the warmer months
Ensure your baby is hydrated
Ensure baby’s room is ventilated
Ensure you check your baby’s temperature regularly

What to do if your baby is overheating

If when you check on your baby, there are signs of overheating such as sweating or flushed cheeks, you can:

Remove some clothing or change to something lighter
Reduce the temperature grade of your baby’s sleeping bag or swaddle
Ensure your baby is hydrated

Ensure the room your baby is sleeping in is properly ventilated
Move your baby’s cot to a cooler room if safe to do so

The signs that your baby is too cold at night

If your baby is too cold at night, they will likely be uncomfortable. Some signs that your baby might be too cold are:

Shivering
Pale complexion
Skin is cold to the touch
Unsettled and waking frequently
Fussiness

How to keep your baby warm at night

To keep your baby warm at night there are a few things you can do. Firstly, you should check the temperature of the room your baby is sleeping in and make sure your little one is dressed appropriately for that temperature. Some ways you can do this are:

Dress your baby in lightweight, breathable layers so you can adjust them as required
Add a sleeveless bodysuit underneath baby’s romper if they’re not warm enough
Add a pair of breathable socks if your baby is feeling too cold
Use a sleep bag or swaddle with an appropriate temperature rating so that your baby’s comfort temperature stays consistent overnight and there’s no chance it can come loose

How to dress your baby for the right temperature

For changing temperatures, it’s a good idea to dress your little one in breathable and well-fitting layered clothing so that you have the option to add or remove layers according to how comfortable your baby is.

For sleep, check the room temperature to ensure you choose a combination of sleepwear that will be suitable. You could use a romper or bodysuit, or a bodysuit with leggings depending on the temperature. If your baby still feels cold, you could consider adding a sleeveless bodysuit under their romper or using a pair of lightweight, breathable socks.

Use a TOG rated sleeping bag or swaddle suitable for the temperature of the room. Our Temperature rating guide provides suggestions of combinations you could use for a range of conditions, from hot to cold temperatures.

Common FAQs from parents

Keeping your baby at their most comfortable temperature can seem complex but it doesn’t have to be. Here we cover some common concerns from parents and caregivers when it comes to knowing when their baby is too hot or too cold.

Will my baby cry if it’s too hot or cold at night?

Babies are more likely to cry if they are cold at night, than if they are hot. This is because if a baby is overheating they may become lethargic and not as responsive.

Will my baby wake up if they are too hot or cold?

Babies are more likely to wake up or present as fussy if they are cold, often in line with a temperature drop. Babies are not as likely to wake up if they are hot, because they can become lethargic and less likely to be awoken.

How do I know if my baby is too hot in a swaddle?

If your baby is too hot in their swaddle you may notice sweating, damp hair, heat rash, flushed cheeks or rapid breathing.