Find the ideal sleep temperature.
Falling asleep depends on core body temperature dropping, which a cool room accelerates — the usual recommendation sits between 16 and 19 degrees Celsius. Bedding shifts that: a light sheet needs a warmer room and a winter duvet a cooler one. Sleeping hot lowers the target further, and humidity above 60% reduces evaporative cooling, so the ideal temperature falls slightly as the air gets damper.
Ideal sleep temperature
Ideal C = 18.5 + bedding adjustment (+1 light / 0 medium / -1.5 heavy) - 1 if you sleep hot - 0.05 per percentage point of humidity above 60, clamped to 15-22 C
These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
Most adults sleep best between 16 and 19 degrees Celsius, adjusted for bedding. The mechanism is the drop in core temperature that initiates sleep, which a warm room blocks.
Core temperature falls in early sleep and rises again toward morning. Heavy bedding or a warm room turns that natural rise into overheating and a wake-up.
Yes. Above about 60% relative humidity, sweat evaporates poorly and the same air temperature feels warmer, which is why the target drops in humid rooms.