Baby Room Temperature and What to Wear to Bed: A UK Winter Guide

The heating has gone on, it's dark by five, and in a lot of houses this week the same question comes up at bedtime: is the baby too cold at night, or too hot? It's a fair worry. Babies can't kick off a layer or tell you they're sweating, and getting it wrong in either direction disturbs sleep. On the hot side, it also matters for safety.

The short answer: keep your baby's room at about 16 to 20°C. Check their temperature by feeling their chest or the back of their neck, not their hands or feet, which are usually cooler. Dress them for sleep in a well-fitting baby sleeping bag or lightweight blankets, with no hat, duvet or pillow, and take a layer off if their skin feels hot or sweaty. That's the Lullaby Trust and NHS advice, and it applies all year round.

The safe room temperature for a baby

The Lullaby Trust and the NHS both recommend a room temperature of 16 to 20°C for a sleeping baby. The Lullaby Trust is clear that this is a guide, not a strict rule. A room at 15°C on a cold night isn't an emergency; it's a cue to add a layer or use a warmer sleeping bag.

The top of the range matters more than the bottom. The NHS says overheating can increase the risk of sudden infant death syndrome (SIDS), and that babies can overheat from too much bedding or clothing, or because the room is too hot. A cheap room thermometer near the cot takes the guesswork out, as long as it isn't sitting on a radiator shelf.

How to tell if your baby is too hot or too cold

• Feel their chest or the back of their neck. This is the check both the NHS and the Lullaby Trust recommend.
• Cool hands and feet are normal. The NHS says not to worry about them, so don't add layers because their fingers feel chilly.
• Hot or sweaty skin means take off a layer of clothing or bedding.
• A chest that feels cool means add a layer, or switch to a warmer sleeping bag.

What should a baby wear to bed in winter?

There's no official chart for this, and that's deliberate. The Lullaby Trust says it can't give clothing or tog advice for each temperature, because fabrics insulate differently, layers add up, and every baby is different. So the honest method is: start from the room temperature, dress your baby sensibly, then check them.

A common starting point on a cold night is a vest and a sleepsuit under a sleeping bag. In a warm room, a vest alone under a lighter bag may be plenty. Whatever you choose, the chest check is what tells you whether it's right.

Sleeping bags and tog ratings

A tog rating measures how warm a sleeping bag is: the higher the number, the warmer. Baby sleeping bags are commonly sold as 0.5, 1.0 and 2.5 tog, and each maker prints a guide to the room temperatures it suits. Use that guide with your room thermometer, then check your baby.

The National Child Mortality Database issued a safety notice on baby sleeping bags after a Which? test found that only 3 of 15 bags from well-known brands and online marketplaces passed all of its tests. Its checklist is worth running through before you buy, especially second hand or from a marketplace:

• The tog should be clearly marked and suit the room, generally between 0.2 and 3.5 tog.
• Look for the safety standard BS EN 16781:2018 on the label.
• It should fit well around the shoulders, so your baby's head can't slip down inside, and the neck opening shouldn't be too wide.
• Choose the right size for your baby's age.
• Avoid bags with hoods or lots of extra material.
• Buttons, fasteners and linings should be secure, with nothing loose.
• Extra bedding shouldn't be needed on top.

Using blankets instead

Blankets are fine if you prefer them. The NHS says to use lightweight blankets, sheets or a baby sleeping bag, and to put your baby down on their back in the "feet to foot" position, with their feet at the bottom of the cot or Moses basket, so they can't wriggle down under the covers. Keep the cot clear of anything that could cover their face or head.

Leave these out for any baby, whatever the weather: duvets, quilts, pillows, cot bumpers, loose blankets, soft toys, and pods or nests. The NHS lists all of them.

Hats, coats and the car

Babies shouldn't wear a hat to sleep indoors. The Lullaby Trust explains that babies lose heat through their heads, so a hat can make them too hot. On winter outings, the NHS says to take off hats and extra clothing as soon as you come indoors or get into a car, bus or train, even if your baby has dropped off. It's fine for a baby to fall asleep in a car seat while you're travelling, but take them out once you arrive.

Should you leave the heating on overnight?

Usually not. The Lullaby Trust says it's rarely necessary to keep the heating on all night, and suggests adding a layer first. If you do leave it on, keep it low and no higher than 20°C. Wherever the cot is, keep it away from radiators, heaters and fires, and out of direct sunlight. The NHS says babies should never sleep with a hot water bottle or an electric blanket.

The NHS also recommends that your baby sleeps in a cot or Moses basket in the same room as you, for every sleep, for at least the first 6 months. A thermometer in your own bedroom covers both of you.

If your baby has a cold or a temperature

It's tempting to bundle up a poorly baby. The Lullaby Trust says not to wrap an unwell baby up more than usual. Dress them as you normally would for the room, and call your GP or NHS 111 if you're worried. Get urgent medical help if they seem seriously unwell.

When the clocks change and the heating goes on

Late October brings two changes in the same week: the clocks go back and the heating comes on. If nights fall apart, it helps to know which one you're dealing with, or whether it's something else entirely, like a cold or a new tooth. A few nights of logged sleep make that much easier to see than memory does at 3am. CubTrack logs sleep and night wakings on the free tier, and you can share the timeline with your partner for free. For the clock change itself, our clocks go back guide has a plan for shifting bedtime.

Related reading

• When the clocks go back: baby sleep
• Baby bedtime routine by age
• The 4-month sleep regression
• Wake windows by age chart
• Teething symptoms and what helps

Frequently asked questions

What temperature should a baby's room be?

About 16 to 20°C, according to the Lullaby Trust and the NHS. It's a guide rather than a strict rule: check your baby's chest or the back of their neck and adjust their layers to suit.

Is 15°C too cold for a baby's room?

It's a little below the recommended range, but not dangerous in itself. Add a layer or use a warmer sleeping bag, then feel your baby's chest. If it's warm and dry, they're fine.

What tog sleeping bag does my baby need in winter?

There's no official tog chart, because fabrics and layers vary. Use the room temperature guide on your sleeping bag's label, alongside a room thermometer, and check your baby's chest. The National Child Mortality Database says the tog should suit the room, generally between 0.2 and 3.5.

Can my baby sleep in a sleeping bag and a blanket?

Extra bedding shouldn't be needed with a well-fitting sleeping bag. If your baby feels cool, add a layer of clothing underneath or use a warmer bag instead of putting a blanket on top.

Should my baby wear a hat to bed?

No. Babies shouldn't wear hats indoors, because they lose heat through their heads and a hat can make them too hot. Take hats off as soon as you come indoors.

Should I leave the heating on at night for my baby?

The Lullaby Trust says it's rarely necessary. Try an extra layer first. If you do leave the heating on, keep it low and no higher than 20°C, and keep the cot away from radiators.

How do I know if my baby is cold at night?

Feel their chest or the back of their neck. If it feels cool, add a layer. Cold hands and feet on their own are normal and aren't a sign your baby is too cold.

Room temperature, clothing and bedding advice checked against The Lullaby Trust and the NHS, and the sleeping bag checklist against the National Child Mortality Database's safety notice, in October 2026. This is general information, not medical advice; speak to your health visitor or GP about your baby. CubTrack is made by OakFox Limited.