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SleepUncovered

Best room temperature for sleep

Updated16 May 2026Read time5 minReviewed bySleepUncovered editorial

Short answer

Moderate evidence

The optimal bedroom temperature for sleep is 16–19°C (60–67°F). This range allows your core body temperature to drop by the ~1°C needed for sleep onset. Above 24°C, sleep measurably degrades: more awakenings, less slow-wave sleep, suppressed REM.

Key points

  • Core temperature drops 0.5–1°C during sleep, with the lowest point around 4–5am.
  • A cool room makes that drop physiologically easy. A warm room slows it.
  • Above 24°C, sleep fragments measurably. Most homes are warmer than this in summer.
  • Bedding lets you tune within the range — layered, breathable materials are most adaptable.
  • A warm shower 60–90 min before bed actually helps via counter-cooling, despite being warming.

The range and why

The 16–19°C (60–67°F) range is the consensus from controlled sleep lab studies. Below 16°C, shivering disrupts sleep onset for some people. Above 19°C, sleep becomes increasingly fragmented as the room gets warmer.

The mechanism is core temperature drop. Sleep onset requires the body to shed roughly 1°C of heat. It does this primarily through vasodilation in the hands, feet, and face — warm blood routes to the skin, heat radiates away. A cool room makes the gradient easy. A warm room fights it.

How warm is too warm

Studies in semi-controlled bedroom temperatures show:

  • 21–24°C: subtle effects in some people, often unnoticed.
  • 24–28°C: measurable sleep fragmentation, reduced slow-wave sleep.
  • Above 28°C: significant sleep loss for most people.

Most centrally-heated UK homes run at 20–22°C overnight without active cooling, which is above optimal but not catastrophic. UK summer nights can run above 24°C inside and produce meaningfully worse sleep.

Practical adjustments

  • Thermostat: set bedroom 1–2°C lower than living spaces. Lower the heating overnight in winter.
  • Bedding layers: thinner duvet, breathable cotton or linen sheets, multiple thin layers rather than one thick.
  • Pre-bed shower: 40°C, 10–15 min, 60–90 min before bed. Counter-cooling kicks in by bedtime.
  • Cool extremities: if you sleep hot, leave one foot uncovered or use cooling gel pads under feet.
  • Cooling mattresses or chillipads: moderate evidence for chronically hot sleepers; expensive.

Hot weather and sleep

Heat waves measurably degrade population sleep. During warm nights:

  • Cool the room before bed if possible (fan, AC, ventilation).
  • Pre-cool the bed (cool damp cotton sheets shed heat as they evaporate).
  • Hydrate during the day; mild dehydration worsens thermoregulation.
  • Avoid alcohol — it suppresses thermoregulation and worsens hot-night sleep.

Cold-room caveats

If you're shivering or feeling actively cold at bedtime, the room is too cold. Some people sleep best at the warmer end of the range; some at the cooler. The 16–19°C range is population-average; individual variation exists. The signal that you're in the wrong zone is fragmented sleep or thermal discomfort — adjust 1°C at a time and reassess.

Sleep with a partner of different preferences

Common issue. Some practical solutions:

  • Different duvets or weighted blankets per side.
  • One person uses a cooling mattress pad on their side.
  • Open one side of the bedroom window for the hotter sleeper.

Room temperature is the priority; bedding can adjust around it.

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