What Should Baby Wear to Bed? A Safe Sleepwear Guide by Temperature

As a simple rule, dress your baby for sleep in about one more layer than you would be comfortable wearing in the same room, and use a wearable blanket or sleep sack instead of any loose bedding.

Getting sleepwear right matters for two reasons: comfort and safety. Loose blankets are a suffocation and overheating risk for babies under a year, and overheating itself is linked to a higher risk of sleep-related death. The good news is that safe, comfortable sleepwear is simple once you know the basics.

This guide covers how to dress your baby by room temperature, why a sleep sack is the safe alternative to blankets, how to check for overheating, and how sleepwear changes as your baby grows.

The One-Layer Rule

The easiest way to dress a baby for sleep is to think about what you would wear to be comfortable in the room, then add one light layer. If you are comfortable in a t-shirt, your baby might wear a onesie plus a sleep sack. If the room is cooler, that could be a long-sleeved footed sleeper plus a sleep sack.

Babies are not better than adults at regulating their temperature, and overdressing is a more common mistake than underdressing. When in doubt, err toward slightly cooler rather than warmer, because overheating carries real risk.

What to Wear by Room Temperature

Room temperature is the main thing to dress to. Most sleep experts suggest keeping the nursery around 68 to 72 degrees Fahrenheit. Here is a practical starting guide. Sleep sacks are sold with warmth ratings called TOG, and a higher TOG is warmer, which can help you fine tune.

Room temperature	A reasonable sleepwear combination
About 74 F or warmer	Short-sleeve onesie, or diaper only under a light sleep sack
About 70 to 73 F	Short or long sleeve onesie under a light sleep sack
About 68 to 69 F	Long-sleeve footed sleeper under a sleep sack
Below about 68 F	Footed sleeper plus a warmer, higher TOG sleep sack

These are starting points, not rules. Every baby and home is different, so use your baby’s own comfort as the real test.

Why a Sleep Sack Instead of a Blanket

The AAP is clear that the safest sleep surface for a baby under a year is completely bare: a firm flat mattress with a fitted sheet and nothing else, including no loose blankets, quilts, pillows, or bumpers.² Loose bedding is a suffocation hazard and can also cause overheating.

A wearable blanket or sleep sack solves the problem neatly. It keeps your baby warm without anything loose in the crib, and because it cannot ride up over the face, it stays safe all night. For swaddling in the newborn weeks, a snug swaddle serves the same purpose, but stop swaddling and move to a sleep sack as soon as your baby shows any sign of rolling. Our guide on when to stop swaddling covers the timing.

How to Check for Overheating

Hands and feet are a poor thermometer. Babies often have cool hands and feet even when they are perfectly warm, so a chilly hand does not mean your baby is cold. Instead, feel the chest, tummy, or the back of the neck, which should feel comfortably warm, not hot or sweaty.

• Signs of overheating: sweating, damp hair, flushed cheeks, rapid breathing, hot chest or neck.
• If your baby seems hot, remove a layer or lower the room temperature.
• Avoid hats for sleep indoors, since babies release heat through the head.

How Sleepwear Changes as Baby Grows

In the newborn stage, a swaddle plus a light layer underneath works well for many babies. Once rolling begins, usually somewhere around three to six months, swaddling must stop, and a sleep sack becomes the go-to for the rest of the first year and often beyond.

Loose blankets are generally considered safe only after the first birthday, and even then many families stick with a wearable blanket for warmth and simplicity. For older babies and toddlers, our guide to the best toddler sleep sacks can help, and a consistent bedtime routine remains one of the strongest tools for good sleep at any age.³

When to Talk to Your Pediatrician

• You are unsure how to dress a premature baby or one with a medical condition for sleep.
• Your baby frequently wakes hot and sweaty despite light clothing and a cool room.
• Your baby seems persistently cold, mottled, or is not feeding or growing well.
• You have any question about safe sleep setup or overheating risk.

When it comes to safe sleep, there is no such thing as a silly question. Your pediatrician can give guidance tailored to your baby and your home.

Frequently Asked Questions