What this is about
An evening weather forecast can fool you. Outside it might be chilly and damp, while an upstairs bedroom is still holding onto afternoon heat. Or a drafty corner drops several degrees once the heating clicks off. The thermometer right beside the crib is the only number that should decide bedtime clothes.
What temperature should a baby's room be?
Keep the room at 16–20°C (61–68°F). A baby is safer a little cool than too warm, because getting too hot raises the risk of SIDS. Plenty of bedrooms are warmer than 20°C (68°F), and that's fine as long as your baby wears less.
Good: Read it by the crib
Put a small thermometer next to the mattress, away from radiators, sunny windows and drafts. It reads the air your baby sleeps in. A baby monitor that shows the temperature works too.
Not good: Not on the hall thermostat
It reads the hallway, and the bedroom can be warmer or cooler than the hall.
No thermometer? Dress your baby in one layer more than you would wear in that room.
Sleep bag, sleepwear or swaddle: pick one
There are three ways to dress a baby for sleep: a sleep bag, fitted sleepwear alone, or a swaddle. Each needs different clothes in the same room, so pick yours first.
Newborn to toddlerSleep bag
A wearable blanket that zips over the clothes. Your baby can't kick it off or pull it over the face.
- Good: Stays on all night
- Good: Works in your bed too
- Not good: Needs a new size as your baby grows
- Not good: Summer needs a lighter one
Any ageSleepwear
A fitted sleepsuit (footie pajamas, in the US), with a bodysuit under it when the room is cooler. At 22–23°C (72–73°F), the sleepsuit alone is enough.
- Good: Nothing extra to buy
- Good: Works in your bed too
- Not good: Needs more layers in a cold room
NewbornsSwaddle
Wraps the arms in to calm the startle reflex, a sudden jerk that can wake a newborn. It's optional, and some babies don't like it.
- Good: Can help a newborn settle
- Not good: Only until the first try to roll
- Not good: Never in your bed
Whichever you pick, lay your baby on the back, with the head uncovered, on a firm, flat mattress with a fitted sheet. Nothing else goes in the crib: no pillows, bumpers, toys or loose blankets.
What TOG means, and what goes under a sleep bag
Every sleep bag (a sleep sack, in the US) has a TOG, a number for how warm it is. A 0.5 TOG bag is thin, for a warm room, and a 2.5 TOG bag is padded, for a cool one.
Under the bag goes a bodysuit, with long or short sleeves for the room. At 22°C (72°F), that means a short-sleeve bodysuit under a 1.0 TOG bag.
Good: The bag alone
Zipped up, with nothing over it. Its TOG and the clothes under it do the warming.
Not good: A blanket on top
A blanket can slide over your baby's face, and layers trap warm air, so it's warmer than it looks.
What to wear to sleep at each room temperature
Tonight's outfit depends on your baby's room and on how your baby sleeps. A sleep bag adds warmth of its own, so fewer clothes go under it. Without one, the clothes do all the warming. In your bed, your body warms your baby too. Choose how your baby sleeps and set the thermometer to your room. You'll see what to put on tonight, piece by piece.
Find the right sleep outfit for tonight
Your room tonight
20°C 68°F
Move the thermometer to your room's temperature.
Long-sleeve bodysuit, 1.0 TOG Medium sleep bag
Long-sleeve bodysuit- 1.0 TOGMedium sleep bag
What does your baby sleep in?
Where does your baby sleep?
Hot nights and cold nights
On a hot night
Dress your baby lighter and cool the room before bed. At 28°C (82°F) and warmer, a diaper alone is enough.
- Good: Close the curtains during the day
- Good: Open the window and the door at night
- Good: Point a fan or the AC away from your baby
On a cold night
Below 16°C (61°F), warm the room a little if you can.
- Good: Keep the crib away from radiators and heaters
- Good: If your baby's chest feels cool, add a layer of clothing
If your baby sleeps in your bed
Next to you, your baby shares your body warmth. You count as a layer, so the outfit is one step lighter than in the crib: at 20°C (68°F), a short-sleeve bodysuit under the 1.0 TOG bag instead of a long-sleeve one.
- Keep the sleep bag on. It's your baby's own bedding, and it comes along if your baby joins you in the night.
- Keep your duvet at your waist and pillows away from your baby.
- Don't swaddle in your bed. Next to you, your baby sleeps with the arms free.
How to dress a newborn for sleep
The first weeks are a special case. A newborn sleeps most of the day and night, often in a bassinet next to your bed, and many parents swaddle. The rule for clothes stays the same, though: dress by the room, as for an older baby. The extra light layer newborns wear is for going outside.
A sleep bag fits once your newborn reaches the smallest size's minimum weight. That weight is on the label. Until then, a swaddle or fitted sleepwear works.
First tries at rolling can come as early as 2 months, and rocking onto a shoulder already counts. That's when to stop swaddling, because a swaddled baby who rolls onto the tummy can't push up with the arms. From then on, your baby sleeps with the arms free, in a sleep bag or in sleepwear.
Questions parents ask
What should my baby wear under a sleep sack?
A bodysuit (a onesie, in US shops): short sleeves under a 0.5 TOG bag, long or short under a 1.0 TOG, long under a 2.5 TOG. At 17°C (63°F) and below, a footed sleepsuit goes under the 2.5 TOG instead. The bag covers the legs, so no pants are needed.
Should my baby wear a hat to sleep?
No. Babies lose heat through the head, so a hat indoors can make your baby too hot.
Can my baby wear socks to sleep?
Yes, if the feet are bare. At 17°C (63°F) and below without a sleep bag, warm socks go with a footless quilted sleepsuit. A footed sleepsuit or a sleep bag already covers the feet.
When can my baby sleep with a blanket?
From 12 months. Before that, a sleep bag keeps your baby warm with nothing loose in the crib. If you'd rather use a thin cotton blanket sooner, tuck it in firmly no higher than the shoulders, with your baby's feet touching the foot of the crib.
What should my baby wear for a nap?
The same as at night: dress for the room. For a nap in the stroller, dress for the weather outside.
What if the room gets colder overnight?
Dress for the temperature the room holds most of the night, not the warm hour at bedtime. If you're up for a feed, feel the chest and change one layer if it needs it.
What should my baby wear to bed with a fever?
The usual outfit for the room. A fever is no reason to bundle up, or to switch to a much lighter bag.
Signs of overheating
- The chest or back of the neck feels hot or clammy.
- Sweaty neck, damp hair, or heat rash.
- Flushed cheeks or fast breathing.
Remove a layer or switch to a lighter bag immediately, and air the room if possible. Call emergency services now if your baby is floppy or hard to wake. Contact your pediatrician if your baby otherwise seems unwell.
