The Ideal Room Temperature for Sleep

If you struggle to fall asleep when it’s too warm, there’s a biological reason. To initiate sleep, your body lowers its core temperature, and a cool bedroom helps that happen. Set the room wrong and you fight your own physiology all night.

The sweet spot: 16–19°C (60–67°F)

Sleep researchers broadly agree that a bedroom around 18°C (65°F) is ideal for most adults, with a comfortable range of roughly 16–19°C. Cooler than that and you may wake up chilled; much warmer and you’ll toss, turn, and sleep more lightly.

Babies and young children do well slightly warmer — around 18–20°C — but the same principle applies: cool, not cold.

Why the “felt” temperature still matters at night

A bedroom thermostat reading of 18°C doesn’t guarantee the same comfort every night. Cold exterior walls in deep winter pull warmth from the bed area, while a stuffy, humid room in summer feels warmer than the number suggests. So the outdoor weather should nudge your bedroom setting, just as it does elsewhere in the home.

Practical tips for better sleep temperature

Lower the heating before bed, not at bedtime — let the room settle to its target.
Use breathable bedding; layers let you fine-tune without changing the thermostat.
In summer, ventilate at night when outdoor air is cooler than indoor air.
Manage humidity. Air that’s too dry irritates airways; too humid feels clammy. Around 40–50% relative humidity is comfortable.

Get the number right for tonight

Because the right bedroom setting depends on tonight’s weather, a fixed thermostat schedule is only an approximation. SetMyTemp factors in the live temperature, humidity and wind so you can set your bedroom for genuine comfort rather than a guess.

Frequently asked questions

What is the best temperature for a baby’s room? Around 18–20°C (64–68°F) is widely recommended — comfortable but not overheated.

Why do I sleep badly when it’s hot? Warm rooms prevent your core temperature from dropping, which your body needs to fall and stay asleep. Cooling the room — or ventilating at night — helps.

See what tonight calls for in your city, or open the SetMyTemp tool.