What is the ideal room temperature for a baby?
Aim for 16–20°C in your baby's room, then check their chest or the back of their neck and adjust one layer at a time.
Current UK guidance recommends 16–20°C for the room where your baby sleeps. Treat this as a useful range, not one perfect thermostat setting or a guarantee that your baby is comfortable or well.
A room thermometer can help you understand the environment, but it does not measure your baby's body temperature. Feel your baby's chest or the back of their neck too. Cool hands and feet are common and, on their own, do not mean that your baby needs more layers.
If your baby otherwise seems well, make one small change at a time: remove a clothing or bedding layer if their chest or neck feels hot or sweaty, or add a clothing layer if their chest feels cold. Then reassess before making another change.
What the 16–20°C range means
The Lullaby Trust and NHS Best Start in Life both give 16–20°C as the recommended or comfortable range for the room where a baby sleeps. The range allows for real homes and individual babies. You do not need to force the room to one exact number when your baby otherwise seems well and their chest or the back of their neck feels comfortably warm.
A room thermometer is useful because room temperature can be difficult to judge by feel. Treat its reading as context, not a medical measurement or proof that your baby is comfortable. Do not trust a room thermometer, thermostat or baby-monitor sensor on its own to judge your baby.
Keeping the room and sleep clothing from becoming too warm matters because overheating is associated with a higher risk of sudden infant death syndrome (SIDS). That association does not mean that one temperature, outfit or device can guarantee safety or prevent SIDS. Keep following the usual safer-sleep guidance as well as monitoring warmth.
How to tell if your baby is too hot or cold
Check the chest or back of the neck
When checking your baby, feel their chest or the back of their neck. If either area feels hot or sweaty, remove a layer. If the chest feels cold, adding a clothing layer may be appropriate. Hands and feet are often cooler than the rest of the body, so they should not be the deciding check on their own.
Touch can guide a routine clothing adjustment, but it cannot measure body temperature, diagnose illness or show that a baby is definitely well. If your baby seems unwell, follow the separate care guidance below.
Make one change, then reassess
For a baby who otherwise appears well, keep the response simple:
- Check the room temperature.
- Feel your baby's chest or the back of their neck.
- Remove a clothing or bedding layer if they feel hot or sweaty, or add a clothing layer if their chest feels cold.
- Reassess your baby rather than continuing to add or remove layers automatically.
If you are still worried, your baby seems unwell, or the problem is not simply about the room or clothing, contact your GP surgery or NHS 111. A routine touch check should never override your concern or delay medical advice.
What should a baby wear to sleep?
There is no single outfit that is right for every baby, product and room. At 16–20°C, light bedding or a lightweight, well-fitting sleep bag can be suitable options. Keep your baby's head uncovered indoors and make sure the cot or sleep space is away from radiators, heaters and direct sunlight.
Start with light layers and follow the product instructions
TOG describes insulation: a higher TOG means a warmer product. Follow the instructions for the particular sleep bag or sleepwear you are using, including its guidance on clothing underneath. Materials, layers, trapped air and individual babies vary, so a universal room-temperature and TOG chart can create false certainty.
Never add a blanket over a sleep bag, use two sleep bags together or add TOG values together. If you use blankets rather than a sleep bag, keep them lightweight and remember that folding a blanket creates extra layers. Avoid pillows, duvets, thick or heavy bedding, weighted bedding, cot bumpers, pods, nests, sleep positioners and other loose or bulky items in the sleep space.
On warmer nights
When the room is above 20°C or the weather is very hot, use lighter layers and keep checking your baby. On the hottest nights, a short-sleeved vest or only a nappy may be appropriate, while all the usual safer-sleep guidance still applies.
Safe ventilation can help. Close curtains during the day if this reduces direct sun, and if you use a fan, do not aim it directly at your baby.
When the room is cooler
If your baby's chest feels cold, add a clothing layer or follow the sleep product's instructions for a warmer option, then reassess. Do not use a hot-water bottle or electric blanket, put an extra blanket over a sleep bag, or position the cot beside a radiator, heater or fire.
A cool room does not make hats indoors or direct heat safe. Keep bedding light and your baby's head uncovered. If a healthcare professional has given individual advice for your baby, including if they were born prematurely, had a low birth weight or have a medical condition, follow that advice rather than a general clothing rule.
When to seek medical advice
Room temperature and body temperature are different measurements. A room thermometer or baby-monitor sensor cannot tell you whether your baby has a fever. If you suspect fever, the NHS fever guidance advises using a digital thermometer under the armpit. A high body temperature is 38°C or more.
A bath or being wrapped in a blanket can temporarily raise a body-temperature reading, so wait a few minutes and check again. If your baby has a fever or seems unwell, dress them for the environment rather than wrapping them in extra clothes, and seek advice from your GP surgery or NHS 111. This is not the same as making a routine sleep-clothing adjustment for an otherwise well baby.
Contact the GP surgery or NHS 111 now
Also seek advice now if a fever lasts 5 days or more, your baby is not their usual self and you are worried, they are not feeding or eating normally, or they show signs of dehydration such as drier nappies. Contact the GP surgery or NHS 111 if you remain worried or your baby seems unwell, even when the concern does not match a simple room-temperature problem.
Call 999
You do not need to wait for several signs to appear. The purpose of this list is to show when emergency help is needed, not to identify the cause.
