What Should Baby Wear to Sleep? Room Temperature and TOG Chart
Standing over the crib at bedtime, second-guessing whether your baby is too hot or too cold, is one of the quiet anxieties of new parenthood. Dress them too warmly and you worry about overheating; too lightly and you picture a chilly, restless night. The good news is that dressing a baby for sleep is more forgiving than it feels, and it comes down to a few simple rules plus a chart you can glance at. This guide covers ideal room temperature, the one-layer rule, safe sleepwear, and a TOG chart to match sleep sacks to the temperature in the room.
The One-Layer Rule
The simplest guideline, and the one echoed by the American Academy of Pediatrics (AAP), is this: dress your baby in no more than one additional layer than you would wear to be comfortable in the same room. If you are cozy in a t-shirt, your baby needs roughly a bodysuit plus one light layer, not a snowsuit.
The AAP's core concern is overheating, which is associated with an increased risk of sudden infant death syndrome (SIDS). When in doubt, it is safer to err slightly cool than too warm. A baby who is a touch cool will usually let you know; overheating is quieter and more dangerous.
What Room Temperature Is Best?
There is no single magic number, and it helps to be honest about that. The AAP does not mandate an exact temperature; its guidance is to keep the room at a comfortable level for a lightly clothed adult and to avoid overheating. In the UK, the NHS and the Lullaby Trust suggest a room temperature of roughly 16–20°C (about 61–68°F) as a comfortable target for baby sleep.
In practice, most families aim somewhere in the range below and then adjust based on how their baby actually looks and feels:
| Setting | Approximate range |
|---|---|
| Commonly suggested target | 16–20°C / 61–68°F |
| Comfortable for most rooms | up to about 22°C / 72°F |
| Getting warm, dress lighter | above 22–24°C / 72–75°F |
A room thermometer (many sleep sacks and monitors include one) takes the guesswork out of it. But the chart is a starting point, not a rulebook, your baby is the real thermostat.
How to Tell If Your Baby Is Too Hot or Too Cold
Skip the hands and feet, they run cool on almost every baby and will mislead you. Instead, feel the chest, tummy, or back of the neck. It should feel warm, not hot or clammy.
Signs your baby may be overheating:
- Sweating or damp hair
- Flushed cheeks
- Rapid breathing
- A hot, clammy chest or back
- Heat rash
If you see these, remove a layer, lower the room temperature, and reassess. Signs a baby is genuinely too cold are less common indoors but include a cool chest and fussiness that settles once you add a light layer.
Make this a two-second habit rather than a worry: each time you check on your baby, rest a hand on the back of the neck or the chest. Over a week or two you will develop a feel for what "just right" is in your home, and the anxiety fades. Rooms also cool overnight, so a baby who was comfortable at bedtime may need slightly warmer sleepwear for a 5am stretch in winter, which is exactly what a well-matched sleep sack is designed to smooth out.
What Is TOG?
TOG stands for Thermal Overall Grade, a measure of how warm a fabric is. Sleep sacks and wearable blankets are labeled with a TOG rating so you can match the warmth of the sleepwear to the temperature of the room. Higher TOG means warmer.
Common ratings you will see:
- 0.5 TOG — very light, for warm rooms
- 1.0 TOG — light, all-purpose
- 2.5 TOG — warm, for cooler rooms
- 3.5 TOG — extra warm, for cold rooms
TOG Chart by Room Temperature
The chart below reflects the standard guidance printed by sleep sack manufacturers, not a medical body, so treat it as a practical guide and always double-check your baby for signs of overheating. "Under the sack" means the clothing worn inside the wearable blanket.
| Room temperature | Suggested TOG | What to wear under the sack |
|---|---|---|
| 24°C+ / 75°F+ | 0.5 TOG or just a sack | Short-sleeve bodysuit, or nappy only in very warm rooms |
| 21–23°C / 69–73°F | 1.0 TOG | Short or long-sleeve bodysuit |
| 18–20°C / 64–68°F | 1.5–2.5 TOG | Long-sleeve bodysuit, footed pajamas if cooler |
| 16–17°C / 61–63°F | 2.5 TOG | Long-sleeve bodysuit and footed pajamas |
| Below 16°C / below 61°F | 3.5 TOG | Bodysuit and footed pajamas, plus a light extra layer |
If you do not use a sleep sack, apply the same logic with footed pajamas and layers, keeping the one-layer rule in mind. And remember that consistency in the sleep environment supports better naps, our wake windows guide covers the timing side of good daytime sleep.
Safe Sleepwear Rules
Whatever the temperature, a few safety rules from the AAP do not change:
- No loose blankets, quilts, pillows, or bumpers in the sleep space for babies under 12 months. A wearable blanket or sleep sack is the safe way to keep a baby warm without loose bedding.
- No hats indoors for sleep. Babies release heat through their heads, and a hat during sleep can contribute to overheating.
- Swaddle only until your baby shows signs of rolling, then stop. Once a baby can roll, a swaddle becomes a hazard; a sleep sack with arms free is the next step. Our guide on when to stop swaddling walks through the transition.
- Skip weighted sleepwear. The AAP advises against weighted swaddles, weighted sleep sacks, and weighted blankets for infant sleep.
- Keep the sleep space bare. Firm, flat surface, fitted sheet only. Our full safe sleep guide and baby sleep safety checklist cover the complete picture.
Seasonal Tips
- Summer. In a hot, un-air-conditioned room, a short-sleeve bodysuit under a 0.5 TOG sack (or just the bodysuit) is often plenty. A fan for air circulation is fine; just do not point it directly at your baby.
- Winter. Layer with footed pajamas and a higher-TOG sack rather than adding loose blankets. If your home is very cold overnight, a higher-TOG sack is safer than piling on covers.
- When baby is sick. A stuffy nose plus too-warm dressing makes for a miserable night. Keep to the one-layer rule and see our tips on helping a congested baby sleep safely.
When to Talk to Your Pediatrician
Dressing for sleep is usually straightforward, but check in with your pediatrician if:
- Your baby frequently wakes sweating, overheated, or very cold despite appropriate dressing.
- You are unsure how to dress a premature or low-birth-weight baby, who may regulate temperature differently.
- Your baby has a fever and you are unsure how to dress them, fever changes the calculus, so ask.
- Anything about your baby's breathing or color during sleep concerns you. Trust your instinct; you know your baby best.
You can log naps, nights, and room conditions to spot what actually helps your baby settle. Start free with a MyBabyTracker account, or try the free nap calculator to dial in nap timing alongside a comfortable sleep space.
This article is for informational purposes only and is not a substitute for professional medical advice.