The simplest rule for dressing your baby for sleep: one layer more than what you’d wear comfortably in the same room. That single guideline, recommended by the American Academy of Pediatrics, prevents both overheating and getting too cold. But the details matter, especially when you’re standing in the nursery at 2 a.m. wondering if your baby needs more or less clothing. Here’s how to get it right at every temperature and stage.
Set the Room Temperature First
Before choosing what your baby wears, check the room. The recommended nursery temperature is 68 to 72°F (20 to 22°C). This range keeps most babies comfortable in a single layer of clothing plus a sleep sack, and it reduces the risk of overheating, which is an independent risk factor for sleep-related infant deaths.
If you can’t control the temperature precisely (older homes, apartments without central air), that’s okay. You’ll just adjust what your baby wears to compensate. A room that runs warm calls for lighter clothing; a cooler room calls for a thicker sleep sack or an extra layer underneath.
What to Dress Your Baby In
The safest sleep outfit is simple: a well-fitting onesie or footed pajama paired with a wearable blanket (sleep sack). No loose blankets, no pillows, no hats. Wearable blankets are specifically preferred by the AAP over traditional blankets because they eliminate the risk of fabric covering your baby’s face or becoming tangled.
Here’s what works at different room temperatures:
- 73 to 79°F (23 to 26°C): A short-sleeve onesie or just a diaper under a lightweight 0.5 TOG sleep sack. In very warm rooms, a onesie alone may be enough.
- 68 to 73°F (21 to 23°C): A long-sleeve onesie or light pajama under a 1.0 TOG sleep sack. This is the sweet spot for most nurseries.
- 61 to 68°F (16 to 20°C): A long-sleeve onesie or footed pajama under a 2.5 TOG sleep sack. You can also add a thin cotton layer underneath the pajama if the room is at the lower end of this range.
What TOG Means and Why It Matters
TOG is a rating that measures how much warmth a fabric provides. The higher the number, the warmer the garment. Most sleep sacks are sold in three TOG ranges: 0.5 (lightweight, for warm rooms), 1.0 (mid-weight, year-round), and 2.5 (warm, for cooler rooms). Choosing the right TOG for your nursery temperature is the most reliable way to avoid both overdressing and underdressing.
You don’t need to memorize the scale. Just check the temperature in the room at bedtime and match it to the chart above. If your home fluctuates between seasons, having two different TOG sleep sacks on hand covers most situations.
Choosing the Right Fabric
Cotton is the most common fabric for baby sleepwear and a solid default. It’s breathable, soft, and widely available. But bamboo viscose has emerged as a strong alternative for babies who run hot or live in climates with big temperature swings.
Bamboo viscose absorbs roughly four times more moisture than cotton, pulling sweat away from the skin to the fabric’s surface where it evaporates. Its fiber structure contains micro-gaps that allow air to circulate freely, which helps regulate your baby’s skin temperature in both warm and cool conditions. Because bamboo manages heat so efficiently, you can often use a lower TOG rating while still keeping your baby warm enough. If your baby seems sweaty in cotton sleepwear but the room temperature is appropriate, switching to bamboo viscose is worth trying before dropping a layer.
Avoid synthetic fabrics like polyester for sleepwear. They trap heat and moisture against the skin, which works against temperature regulation.
No Hats, No Weighted Sleepwear
It’s tempting to put a cozy beanie on your baby at bedtime, especially in the early weeks. Don’t. The AAP advises against hats for sleeping infants indoors (the exception being the first few hours after birth or in the NICU). Babies release a significant amount of body heat through their heads, and covering that escape route raises the risk of overheating. A hat can also slip down over a sleeping baby’s face.
Weighted sleep sacks, weighted swaddles, and weighted blankets are also explicitly not recommended. Despite marketing claims about soothing benefits, these products pose safety risks and have no proven benefit for infant sleep. If you see a “weighted” label on any sleep product, skip it.
Swaddling: When to Start and Stop
Swaddling can help newborns sleep by dampening their startle reflex, that involuntary arm-flinging motion that wakes them up. A proper swaddle wraps snugly around the torso and arms while leaving the hips loose enough to bend and move freely. Use a thin, breathable fabric and count the swaddle as one of your baby’s layers when assessing warmth.
The critical rule: stop swaddling as soon as your baby shows any signs of learning to roll over. For most babies, this happens between 2 and 4 months, though some start as early as 8 weeks. Signs to watch for include pushing up during tummy time, lifting their legs and flopping them to one side, or successfully rolling during play. If a swaddled baby rolls onto their stomach, they can’t use their arms to reposition or clear their airway, creating a serious suffocation risk.
Once you retire the swaddle, transition to a sleep sack with open armholes. Many parents find this switch goes more smoothly than expected, especially if they choose a sleep sack with a snug fit around the chest that still provides some of that contained feeling.
How to Tell If Your Baby Is Too Hot
Overheating is a greater concern than being slightly cool. Research consistently links overheating during sleep to increased risk of SIDS. In one well-known study of 34 SIDS cases, 24 infants were excessively clothed or overwrapped, and 19 were unusually hot or sweating when found.
The most reliable way to check your baby’s temperature is to place your hand on their chest or the back of their neck. These areas reflect core body temperature better than hands or feet, which often feel cool even when a baby is perfectly warm. Signs your baby is too hot include:
- Sweating: Damp hair, a sweaty chest, or moisture on the back of the neck.
- Flushed skin: Red cheeks or a blotchy chest.
- Hot chest: If their torso feels noticeably warm to your touch, they likely have too many layers.
- Restlessness: Fussiness or rapid breathing can also signal overheating.
If you notice any of these signs, remove a layer or switch to a lower TOG sleep sack. It’s always safer to add a layer later than to start with too many.
Cold Hands and Feet Are Normal
New parents often panic when they feel their baby’s icy fingers or toes. This is almost always normal. Infants have immature circulatory systems, and blood flow prioritizes their core organs over their extremities. Cold hands and feet do not mean your baby is underdressed. Check the chest or neck instead. If those areas feel warm (not hot) and your baby is sleeping comfortably, the outfit is right.
If you’re still worried about cold feet, footed pajamas solve the problem without adding extra layers or loose socks that could come off and become a hazard in the crib.