Dressing your baby for sleep: Frequently asked questions answered

When it comes to baby sleep, one of the most common concerns parents have is how to dress their little one for bedtime. Is my baby too hot? Too cold? Do they need socks? Should they wear a onesie under their pajamas? And what about blankets—when are those safe to use?

Dressing your baby for sleep is more than just about comfort. It’s also about safety. Overheating has been linked to an increased risk of Sudden Infant Death Syndrome (SIDS), which is why it’s so important to make sure your baby is dressed appropriately for the temperature of their sleep environment. At the same time, you want to ensure your baby is at the ideal temperature and not too hot or too cold to sleep soundly through the night.

Since so many parents have questions about this topic, I’ve put together a comprehensive FAQ guide to help you navigate how to dress your baby for safe and comfortable sleep.

How do I know if my baby is too hot or too cold at night?

A common mistake parents make is checking their baby’s hands and feet to determine if they are too cold. However, because a baby’s circulatory system is still developing, their extremities are often cooler than the rest of their body, even when they are perfectly comfortable. Instead of relying on how their hands and feet feel, the best way to check if your baby is warm enough is by feeling the back of their neck or chest. If their skin feels warm and dry, they are comfortable. If their chest feels cold, they might need another layer. If their back feels sweaty, they are too warm and may need a layer removed.

Overheating is something to watch for carefully, as it can increase the risk of SIDS. If your baby is flushed, sweaty, breathing rapidly, or has damp hair, they are likely too hot. On the other hand, signs that your baby may be too cold include waking frequently, shivering (though rare in young babies), and a noticeably cool chest or back. In general, it’s best to err on the side of too cool rather than too warm when it comes to your baby’s sleep.

What should my baby wear to sleep based on temperature?

The best way to dress your baby depends on the temperature of their room, not the weather outside. Babies sleep best in a room that is between 68-72°F (20-22°C), but if the temperature fluctuates, you’ll want to adjust their clothing accordingly.

In warm weather, when the room is above 75°F (24°C), a simple short-sleeve onesie or even just a diaper with a lightweight sleep sack may be all they need. It’s essential to choose breathable fabrics like cotton or bamboo to allow for proper air circulation and prevent overheating.

For mild temperatures, around 69-74°F (21-23°C), a short-sleeve or long-sleeve onesie paired with a lightweight sleep sack is usually ideal. This provides warmth without being too restrictive.

When the temperature drops to 61-68°F (16-20°C), your baby will likely need a long-sleeve onesie or footed pajamas along with a medium-weight sleep sack. Some babies prefer a bodysuit underneath for extra warmth, but it’s important not to overdress them.

What is a TOG rating, and how do I choose the right one?

A TOG (Thermal Overall Grade) rating measures the warmth of baby sleepwear and sleep sacks. The higher the TOG rating, the warmer the fabric.

For warmer weather, a 0.5 TOG sleep sack is the best choice, as it is light, allows air to circulate and prevents overheating. A 1.0 TOG sleep sack works well for mild temperatures, making it a versatile, year-round option for most families. When the room is on the cooler side, a 2.5 TOG sleep sack provides extra warmth without the need for extra layers. If your home tends to get especially cold in the winter (60°F or 15°C and below), a 3.5 TOG sleep sack is best for keeping your baby cozy without the need for unsafe blankets.

Do newborns need to be swaddled for sleep?

Swaddling is a wonderful way to help newborns feel secure and settled for sleep, as it mimics the snug feeling of being in the womb. Many babies sleep more soundly when swaddled because it prevents their startle reflex from waking them up. However, it’s essential to use a lightweight, breathable swaddle to prevent overheating. For more information about the benefits of swaddling, check out this in depth blog: Should I swaddle my baby for better sleep?

When should I switch my baby from a swaddle to a sleep sack?

Swaddling should be stopped as soon as a baby starts showing signs of rolling, which typically happens around 8-12 weeks old- but can happen earlier in some cases. At that point, swaddling becomes unsafe, and it’s time to transition to a sleep sack, which provides warmth without restricting movement. Read more about this transition out of the swaddle here.

Some parents transition by using a swaddle-transition sleep sack, which allows one or both arms to be left out gradually. Other babies do well moving straight into a standard sleep sack, which still provides warmth and comfort while allowing free movement.

Can my toddler still wear a sleep sack?

Yes! Many toddlers sleep better in a sleep sack because it prevents them from kicking off their blankets at night. Using a sleep sack long term can also be a great deterrent to keep your little one from trying to climb out of the crib. 

Most toddlers and preschoolers aren’t very good at fixing their blankets or get themselves tucked back in until 4+ years of age so continuing to use a sleep sack overnight can help you avoid those pesky night wakings to fix blankets. 

Some parents switch to toddler-sized sleep sacks with foot openings, like the Flying Squirrel PJs from SleepingBaby, which allow for movement while still providing warmth. If you do introduce a blanket, wait until your child is at least 18 months old and use a lightweight, breathable option. But keep in mind that many crib manuals will state that nothing should be added to the crib- even a blanket.

Should I put socks, mittens, or a hat on my baby for sleep?

Babies do not need socks or mittens for sleep unless their room is especially cold (60°F or 15°C and below). Footed pajamas or a sleep sack usually provide enough warmth. Hats should never be worn indoors during sleep, as babies release excess heat through their heads, and a hat can easily lead to overheating.

What if my baby’s hands and feet feel cold at night?

It’s perfectly normal for a baby’s hands and feet to feel cool at night, as their circulatory system is still developing. As long as their chest or back feels warm, they are not too cold and there is no need to worry or add extra layers.

Can my baby sleep with a blanket?

Loose blankets are not safe for babies under 18 months old due to the risk of suffocation. Instead, use a sleep sack to provide warmth and comfort without the risk. If your child is older than 18 months and you decide to introduce a blanket, start with a lightweight, breathable one and avoid heavy quilts or comforters.

Should I dress my baby differently for naps than for bedtime?

In most cases, babies should be dressed the same way for naps as they are for bedtime. This consistency helps reinforce sleep cues and makes it easier for them to settle down. If your home is significantly warmer during the day, you might opt for a lighter sleep sack or skip a layer underneath the sleep sack to prevent overheating. But using a sleep sack both at naptime and at bedtime is a great part of their routine and a helpful cue that it’s sleep time.

Final thoughts

Dressing your baby for sleep doesn’t have to be complicated. The key is to follow temperature guidelines, avoid loose bedding, and watch for signs of overheating or discomfort.

It’s also important to remember that every baby is different—some naturally sleep warmer, while others run cooler. Pay attention to how your baby responds to different sleepwear and adjust accordingly.

If you’re struggling with your baby’s sleep and need personalized guidance, I’d love to help! Schedule a free 15 minute discovery call, and let’s create a sleep plan that works for your family.

Here’s to cozy, safe, and restful nights ahead!