How Does Room Temperature Affect Sleep?

The One Bedroom Change That Transforms Your Sleep

You can get everything else right — the perfect mattress, a consistent bedtime, no screens before bed — but if your bedroom is just a few degrees too warm, your sleep still suffers. Temperature is one of the most overlooked levers in a good night's rest.

The science is clear: most adults sleep best in a cool room of around 18°C. That's because your body has to cool down to fall asleep in the first place. In the hours before bed, your core temperature naturally dips, signalling your brain that it's time to rest — and a warm room works directly against that process, flattening the dip, increasing night-time waking, and stealing the deep and REM sleep that leave you feeling restored. On nights above 30°C, people lose around 14 minutes of sleep on average.

There's a clever trick, too. Warming your body before bed — a warm bath or shower one to two hours beforehand — actually helps your core temperature fall faster, ushering in sleep more quickly. And for couples where one runs hot and the other runs cold, the nightly tug-of-war over the covers finally has an elegant solution.

The good news? You don't need to overhaul your life — just nudge the dial a few degrees. Discover the ideal temperature range for every stage of the night, the fascinating science of your body's built-in sleep thermostat, and the simple changes that make a cool, comfortable bed effortless all year round.

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