How to dress a baby for sleep according to the temperature
How to dress a baby for sleep according to the temperature
You do not need to get it exactly right with a perfect formula. You need to observe the environment, choose a few layers, and learn to read your baby's cues.
Between 16 and 20 °C is generally considered a comfortable temperature. Start with lightweight clothing, check the chest or nape of the neck, and adjust one layer at a time.
Long-sleeved bodysuit, pajamas, sleep sack, blanket… or just a diaper? Dressing a baby for sleep can raise many questions, especially when the temperature changes. The key is not to follow a rigid formula, but to observe the environment, choose lightweight clothing, and check how your baby is doing.
First, listen to the room
The season or outdoor temperature can be misleading. A heated room in winter may be warmer than a cool summer night. Before deciding what to dress your baby in, use a room thermometer near the sleeping area but out of reach.
Safe sleep recommendations generally place the comfortable range between 16 and 20 °C, together with lightweight clothing, lightweight bedding secured firmly, or a suitable, well-fitting sleep sack.
A visual guide to help you
Tap each range to open the recommendation. This is guidance: always follow the manufacturer's size, weight, and TOG guide.
❄️ Below 16 °C · Cool room
You can add a lightweight layer of clothing or choose a warmer sleep sack according to the manufacturer's instructions. If you use a sleep sack, do not place additional blankets over it. Avoid hats and always keep the head uncovered.
✦ Between 16 and 20 °C · Comfortable range
A suitable bodysuit or pajamas together with a well-fitting lightweight sleep sack is often a practical option. Alternatively, use lightweight bedding, tucked in firmly and no higher than the shoulders.
☀️ Over 20 °C · Warm room
Reduce the number of layers and choose breathable clothing. On very hot nights, a lightweight bodysuit or even just a diaper may be enough, checking regularly that the baby is comfortable and not too hot.
Are they too hot?
Do not rely solely on their hands or feet: it is normal for them to feel somewhat cool. Gently touch the chest, tummy, or nape. If the skin is hot, damp, or sweaty, remove a layer.
The most useful check is simple: a warm, dry chest or nape. Damp hair, very flushed cheeks, or faster-than-usual breathing may accompany overheating.
If the baby is ill, has a fever, or anything worries you, consult a healthcare professional.
TOG, explained simply
TOG indicates how much warmth a fabric provides: the higher the number, the greater its insulating capacity. There is no universal chart that precisely combines temperature, clothing, and TOG; materials, layers, and each baby's build change the result.
Check the chart
Follow the manufacturer's specific recommendation.
Check the fit
The sleep sack should correspond to the baby's weight and size.
Neck and armholes
They should prevent the baby from slipping inside.
No blanket on top
Adjust the clothing or sleep sack; do not add loose textiles.
Materials: less can be more
Prioritize lightweight, breathable fabrics such as cotton, and avoid many thick layers. Clothing should allow the baby to move comfortably and should not include cords, hoods, or loose elements for sleeping.
On warm days, a thin layer makes it easier to adjust the temperature. On cold days, it is preferable to add a light layer of clothing rather than overload the sleeping space with loose textiles.
The calm nightly checklist
- Room temperature, ideally between 16 and 20 °C.
- Baby lying on their back.
- Head and face uncovered.
- Firm, flat, clear mattress.
- No pillows, protectors, stuffed animals, or loose bedding.
- Checking the chest or the back of the neck before going out.
The questions that arise at three in the morning
Should I put one more layer on my baby than an adult?
It can be a useful starting point during the day, but for sleep it is more reliable to check the room temperature, the product instructions, and your baby’s chest or the back of their neck.
Can they sleep wearing a hat?
Not indoors. The head should remain uncovered during sleep to help prevent overheating.
What should I do if their hands are cold?
Hands and feet may feel cool even when your baby is comfortable. Check their chest or the back of their neck before adding clothing.
Can I use a blanket over the sleep sack?
It is not recommended. If your baby seems cold, choose an appropriate clothing layer or a warmer sleep sack, always following the manufacturer’s guidance.
You don’t need to find the perfect combination every night. Check the room temperature, start with a few layers, check your baby, and adjust. Comfort and safe sleep matter more than any chart.
Sources consulted: NHS and The Lullaby Trust. This article provides general information and does not replace individual advice from a pediatrician or other healthcare professional.
