Signs Your Baby Is Too Hot Or Cold While Sleeping

Back to Baby Sleep
Essentials
At one time or another, every parent or caregiver has stood over their baby’s cot wondering if they are 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. 
reviewed by Genevieve Titov, Sleep Angel
7 min read |
01 March, 2023

What is the best temperature for a baby at night? 

It is very important to make sure a baby is not too hot or too cold whilst sleeping. The risk of sudden infant death syndrome (SIDS) is higher in babies who get too hot. The Lullaby Trust recommend a room temperature for babies of 16 – 20°C. with light bedding or a lightweight, well-fitting baby sleep bag, is comfortable.

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? 

It is suggested that babies can start 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  

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 TOG 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 TOG rating guide provides suggestions of combinations you could use for a range of conditions, from hot to cold temperatures. 

Common FAQs from parents 

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.  

More from this topic

See all
Baby Sleep

Spaces

Learn how to create a cosy, safe sleep environment with tips on room setup, temperature, and the ideal sleep wear for peaceful slumber.
19 resources
Can Newborns Sleep On Their Side?
How to teach a baby to self-settle and self-soothe

Most popular

See all
How To Dress A Baby In Winter For Sleep
Daylight saving: How to adjust your baby’s sleep routine
Finding You Time with Steph Claire Smith