It's 2 a.m. You're standing over the crib with one hand on your baby's back, asking the same question every mom asks: is she too hot? Too cold? Do I add a layer or take one off?
You're not overthinking it. What your baby wears to sleep affects how long she stays asleep - and, more importantly, how safely. The good news is that it comes down to two numbers: the temperature of the room, and the number of layers on your baby. Once you have a chart for that, the 2 a.m. guessing stops.
Here's the short answer, then the full room temperature chart you can screenshot and keep on your phone.
The short answer
In a nursery kept at 68–72°F (20–22°C), most babies sleep comfortably in a long-sleeve bamboo pajama set or footed zip romper, plus a 1.0 TOG sleep sack. The rule of thumb pediatricians use: dress your baby in no more than one extra layer than you'd be comfortable sleeping in yourself — and skip loose blankets entirely for the first year.
Start with the room, not the outfit
Before you pick pajamas, pick a number. The American Academy of Pediatrics recommends keeping your baby's sleep space at a comfortable temperature and watching for signs of overheating, since overheating is associated with an increased risk of SIDS. In practice, most pediatric sleep guidance lands on 68–72°F (20–22°C).
Three things new moms learn the hard way:
- Put the thermometer where the baby is. The hallway thermostat and the crib can be five degrees apart, especially upstairs.
- Rooms drift overnight. A nursery that reads 71°F at bedtime can sit at 65°F by 4 a.m. Dress for the coldest part of the night, not the warmest.
- Check the vents and the window. A crib under an AC vent or against a drafty window is in a different microclimate than the rest of the room.
The one-layer rule (and how to count a layer)
"One more layer than you" only works if you count layers the same way every night. Here's how:
- A diaper is not a layer.
- A bodysuit or onesie is one layer.
- A pajama set or zip romper is one layer.
- A sleep sack or wearable blanket is one layer.
So a long-sleeve romper plus a sleep sack equals two layers — the right amount for a mom who sleeps in one layer plus a sheet. Simple.
Baby sleep temperature chart: what to wear at every room temperature
This is the chart to save. Find your room temperature on the left, read across.
| Room Temperature | How It Feels | What Baby Wears | Sleep Sack TOG |
|---|---|---|---|
|
🥵 75°F and up 24°C and up |
Hot — summer night, no AC | Diaper only, or a short-sleeve bamboo bodysuit | 0.5 or none |
|
☀️ 72–75°F 22–24°C |
Warm — late spring, early fall | Short-sleeve bamboo romper or short-sleeve pajama set | 0.5–1.0 |
|
🌤️ 68–72°F ⭐ 20–22°C |
The sweet spot — aim for this year-round | Long-sleeve bamboo pajama set or footed zip romper | 1.0 |
|
🍂 64–68°F 18–20°C |
Cool — fall nights, drafty rooms | Long-sleeve bodysuit under a footed romper or pajama set | 2.5 |
|
❄️ Below 64°F Below 18°C |
Cold — winter, unheated rooms | Warm long-sleeve base layer + footed pajamas (still no loose blanket) | 2.5–3.5 |
Every baby runs a little different. Use the chart as your starting point, then use the neck check below to fine-tune it for your baby.
What is a TOG rating, in plain English?
TOG stands for Thermal Overall Grade. It's simply a measure of how much warmth a fabric holds in. Low TOG = light and breathable. High TOG = thick and insulating. It's the same idea as a comforter's fill weight, just for baby sleepwear.
| TOG | Best For | Room Temperature |
|---|---|---|
| 🥵 0.5 TOG | Summer, air-conditioned rooms | 75°F+ / 24°C+ |
| 🌤️ 1.0 TOG | The year-round workhorse | 68–75°F / 20–24°C |
| 🍂 2.5 TOG | Fall and winter nights | 61–68°F / 16–20°C |
| ❄️ 3.5 TOG | Cold, unheated rooms | Below 61°F / 16°C |
If you keep your nursery in the recommended range, you only really need two: a 1.0 TOG for most of the year and a 2.5 TOG for the cold months. That's exactly why our bamboo sleep sacks come in those two ratings and nothing in between — two sacks cover a whole year.
What should baby wear under a sleep sack?
This is the question that trips up most first-time moms, and the answer is easier than it sounds: the sleep sack is a layer, so count it as one.
- 0.5 TOG sack: a short-sleeve bodysuit underneath, or just a diaper on very warm nights.
- 1.0 TOG sack: a long-sleeve bamboo zip romper or lightweight pajama underneath.
- 2.5 TOG sack: a footed romper or full pajama set underneath, and a long-sleeve bodysuit as a base layer if the room drops below 65°F.
What you should not do is stack a heavy sack over a fleece sleeper "just in case." That combination is the most common cause of an overheated, restless baby.
How to dress your baby for sleep by age
Newborn to about 8 weeks
Most newborns settle best swaddled with arms in, over a diaper and a short- or long-sleeve bodysuit depending on the room. A breathable bamboo swaddle blanket gives you the snugness without the heat of a thick muslin.
The moment they start to roll
Stop swaddling at the first sign of rolling — not the first successful roll. This is a firm safety line, not a preference. Swap the swaddle for a sleeveless sleep sack the same night, keeping the room temperature and the layer count the same so the only thing that changes is the arms.
3 to 12 months
This is prime sleep sack territory. A zip romper underneath makes 2 a.m. diaper changes a ten-second job instead of a two-minute one — a small thing that matters enormously when you're the one doing it half-asleep.
12 months and up
Toddlers kick off anything you put over them, which is exactly why a two-piece pajama set or a sleep sack works better than a blanket well past the first birthday. Keep the same chart — toddlers run warm, so if yours is a furnace, size down one TOG before you drop a layer of clothing.
The neck check: how to tell if your baby is too hot or too cold
Hands and feet lie. Babies have immature circulation, so cool little fingers are normal even when your baby is perfectly warm. Feel the back of the neck or the center of the chest instead. Warm and dry means you got it right.
Signs your baby is too hot:
- Damp or sweaty neck, back, or hairline
- Flushed cheeks, skin that feels hot to the touch
- Fast breathing, restlessness, waking more than usual
- Heat rash on the neck, chest, or back
Signs your baby is too cold:
- Chest or back of the neck feels cool
- Waking frequently and struggling to resettle
- Pale or mottled skin tone
Adjust by one layer, not three. If your baby wakes damp at the neck, drop the base layer before you drop the sack — you'll keep the familiar bedtime cue and still cool her down.
5 safe sleep rules that don't change with the weather
- Alone, on the back, in a crib — every sleep, including naps.
- No loose blankets, pillows, bumper pads, or stuffed animals in the crib during the first year. A wearable blanket does the same job without the suffocation risk.
- No hats indoors. Babies release heat through their heads; a hat in the crib is an overheating risk.
- No weighted sleep sacks, weighted swaddles, or weighted blankets at any age. U.S. safety agencies have warned against them.
- Nothing that can cover the face. Check that any sleepwear fits properly and can't ride up over your baby's head.
Why the fabric matters as much as the layer count
Two pajamas that look identical can behave completely differently at 3 a.m. Polyester fleece traps heat and holds moisture against the skin. Bamboo viscose does the opposite: it's highly breathable, moves moisture away from the skin, and helps a baby stay in a comfortable range as the room cools overnight. That's why the same 1.0 TOG feels right across a wider band of temperatures in bamboo than in a synthetic.
It's also why bamboo is the fabric so many moms land on for eczema and sensitive skin. If you want the full picture on the fiber itself, we wrote about it here: why we choose bamboo.
Frequently asked questions
What should a baby wear to sleep at 68 degrees?
At 68°F (20°C), dress your baby in a long-sleeve bamboo pajama set or a footed zip romper, plus a 1.0 TOG sleep sack. If the room drifts closer to 64°F overnight, add a long-sleeve bodysuit as a base layer or move up to a 2.5 TOG sack.
What is the ideal room temperature for a baby's sleep?
68–72°F (20–22°C). Measure it at crib level rather than relying on the hallway thermostat, and dress for the coldest point of the night.
Can my baby sleep in just a diaper?
On a genuinely hot night — 75°F (24°C) and above — a diaper alone or a diaper with a light short-sleeve bodysuit is appropriate. Do the neck check before you commit to it for the whole night.
Do babies need socks or a hat to sleep?
No hats indoors — that's a safe sleep rule, not a preference. Socks are optional and usually unnecessary in a properly warm room; cool feet on their own are not a sign your baby is cold.
When can my baby sleep with a blanket?
Keep the crib bare for the entire first year. After 12 months the risk drops considerably, but most families find a sleep sack or warm pajamas simply works better, since toddlers kick blankets off anyway.
What TOG do I need for winter?
A 2.5 TOG sleep sack covers most heated homes in winter (61–68°F / 16–20°C). Reach for 3.5 TOG only if the room genuinely sits below 61°F. Above that, 2.5 TOG plus a footed pajama is plenty.
Is my baby waking up because she's cold?
Sometimes — a room that drops several degrees after midnight is a classic cause of 3 a.m. wakings. Check the back of the neck when you go in. If it's cool, add one layer. If it's damp, remove one. Give any change two or three nights before you judge it.
How do I dress a newborn for sleep?
A diaper, a bodysuit matched to the room temperature, and a swaddle with arms in — until the first sign of rolling, when the swaddle comes out and a sleeveless sleep sack takes over.
The takeaway
Set the room to 68–72°F. Add one more layer than you'd wear. Check the back of the neck, not the hands. Keep the crib bare. That's the whole system — and it holds up in July and in January.
If you're building your baby's sleep drawer from scratch, the shortlist most moms end up with is two bamboo sleep sacks (one 1.0 TOG, one 2.5 TOG), three or four zip rompers for the everyday nights, and a couple of pajama sets for when she's older. Not sure on sizing? Our size chart takes the guesswork out of it.
Shop bamboo sleepwear made for real nights →
This article is for general information and isn't medical advice. Safe sleep guidance here reflects the American Academy of Pediatrics' recommendations. Always talk to your pediatrician about your own baby.
