Temperature Control and Sleep

Hot and cold – helping your baby sleep comfortably

We all know how much temperature affects sleep. Too hot and you’re tossing the covers off, too cold and you’re hunting for another blanket. For babies, who are still learning to regulate both their body temperature and sleep patterns, the impact can be even greater. If they’re too warm or chilly, they might struggle to drift off – or wake more often through the night.

The good news is you can help keep your baby at a comfortable temperature with the right mix of clothing, bedding, and room adjustments, making it easier for them to settle and stay asleep.

Why temperature matters

Our bodies can regulate internal temperature, but during deep sleep, that process slows down. This means a room that’s too hot or too cold can cause night wakings. For babies, the ideal room temperature is around 18°C – it might sound cool, but a lower core temperature is linked to better sleep, while warmer conditions often mean more restlessness.

A warm bath before bed can also help. While it seems backwards, the water on your baby’s skin will cool them down after the bath, helping them start the night at a comfortable temperature.

Ways to manage temperature

Heaters, fans, air conditioning, and the right bedding can all help keep things steady through the night. If you have a thermostat, set it to 18°C and let it do the work. If not, you can buy a plug-in thermostat for your heater to help maintain consistency.

Merino – your sleep-time secret

When it comes to baby sleepwear, merino wool is a year-round winner. Naturally breathable and temperature-regulating, it helps keep your baby comfortable in both warm and cool conditions – and research shows it can even help them sleep longer.

In winter, use merino layers under a merino sleeping bag or sleepwalker. In summer, lighter cotton or merino sleepwear with a lighter weight sleeping bag is usually enough, depending on the temperature where you are. Sleeping bags are especially useful as they can’t be kicked off like blankets, keeping your baby covered all night. Choose one with a weight (or TOG rating) that suits the season. 

Spotting temperature troubles

Signs your baby might be too hot:

• Waking often
• Sweaty neck or back
• Damp hair
• Rapid, shallow breathing

If you notice these, remove a layer of clothing, switch to a lighter sleeping bag, improve airflow, or lower the room temperature. If your baby seems uncomfortably hot, check for fever and use a cool, damp cloth on their forehead and back.

Signs your baby might be too cold:

• Moving around the cot more than usual
• Rolling onto their stomach during sleep
• Frequent short naps
• Early morning waking (around 5am, when body temperature naturally dips)

If this happens, add a layer, switch to a warmer sleeping bag, or adjust the room temperature.

Getting the temperature right won’t solve every sleep challenge, but it’s one piece of the puzzle that can make nights smoother for everyone.

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