The best temperature for sleep is around 65°F (18.3°C). Most sleep experts recommend keeping your bedroom between 60 and 68°F (15.6 to 20°C), though the sweet spot varies by a few degrees from person to person. This range works because it supports your body’s natural cooling process, which is essential for falling and staying asleep.
Why Cool Rooms Help You Sleep
Your core body temperature starts dropping about two hours before you naturally fall asleep. This decline, roughly 2°F (1°C) over the course of the night, signals your brain that it’s time to transition into sleep. The deepest phase of non-REM sleep is most likely to begin at the steepest point of that temperature drop.
A cool room accelerates this process. Your body sheds heat through your skin, particularly your hands and feet, by dilating blood vessels near the surface. When the air around you is already cool, this heat loss happens more efficiently. Even tiny shifts matter: raising skin temperature by less than 1°F can be enough to shorten the time it takes to fall asleep, because that warmth at the skin’s surface helps push heat out of your core.
A room that’s too warm fights this biology. When ambient temperature climbs above the comfortable range, your body struggles to dump heat. The result is restless sleep, more awakenings, and less time in the deep, restorative stages your body needs most. Research on older adults found a 5 to 10 percent drop in sleep efficiency once bedroom temperatures climbed above 77°F (25°C).
Temperature Needs by Age
Babies, adults, and older adults all have different comfort zones. For most healthy adults, the 60 to 68°F range holds up well. But if you’re setting up a nursery or caring for an aging parent, those numbers shift.
For infants, the recommended range is 68 to 72°F (20 to 22°C). Babies can’t regulate their body temperature as effectively as adults, and a room that’s too warm raises the risk of overheating, which is a known factor in sudden infant death syndrome (SIDS). Dress your baby in one layer more than you’d wear comfortably, and skip heavy blankets.
Older adults tend to sleep best in slightly warmer rooms. A study from Hebrew SeniorLife found that seniors had the most efficient, restful sleep when nighttime temperatures stayed between 68 and 77°F (20 to 25°C). That’s notably higher than the standard adult recommendation. Age-related changes in circulation, metabolism, and body composition make it harder for older adults to stay warm, so what feels comfortable at 30 may feel chilly at 75. The study also found substantial individual variation, meaning there’s no single perfect number for every older adult.
A Warm Bath Helps (Counterintuitively)
Taking a warm shower or bath one to two hours before bed can actually help you fall asleep faster. Water temperature of about 104 to 109°F (40 to 42.5°C) for as little as 10 minutes does the trick. It sounds contradictory, but the warm water draws blood to the surface of your skin. After you step out, that blood rapidly releases heat into the cooler air, accelerating the core temperature drop your body needs to initiate sleep.
A meta-analysis of existing studies found that this simple routine significantly shortened the time it took people to fall asleep and improved overall sleep quality. It’s one of the most accessible, low-cost sleep interventions available.
Bedding Matters as Much as the Thermostat
Your sheets and blankets create a microclimate between your body and the room air. Even if your thermostat reads 65°F, heavy or synthetic bedding can trap heat against your skin and undo the benefit of a cool room.
For hot sleepers, cotton percale and linen are the most breathable, durable options. Percale has a loose, plain weave that doesn’t cling to the body and allows air to circulate freely. Linen is slightly more breathable but has a rougher texture that not everyone loves. Both improve with washing. Be cautious about sheets marketed as “cooling.” That label is mostly a marketing term highlighting an existing property of the fabric, not a special technology. No sheet cools you the way an air conditioner does.
Layering lighter covers instead of using one thick comforter gives you more control. You can kick off a layer when you’re warm in the first half of the night, then pull it back up in the early morning hours when your body temperature bottoms out.
Humidity Plays a Supporting Role
Temperature isn’t the only environmental factor. Humidity affects how efficiently your body can cool itself through evaporation. The EPA recommends keeping indoor relative humidity between 30 and 50 percent, with 60 percent as the upper limit. Some research suggests 40 to 60 percent is a better target range.
When humidity is too high, sweat doesn’t evaporate well, and you feel sticky and warm even if the thermostat is set correctly. When it’s too low, you may wake up with a dry throat, irritated nasal passages, or cracked skin. A simple hygrometer (available for under $15) can tell you where your bedroom falls. A humidifier or dehumidifier can close the gap if needed.
Finding Your Personal Sweet Spot
The 60 to 68°F guideline is a strong starting point, but your ideal temperature depends on your age, body composition, metabolism, what you wear to bed, and your bedding. People with more body fat tend to sleep warmer. People with lower muscle mass or slower metabolisms, common in older adults, tend to sleep cooler. Hormonal fluctuations during menstruation or menopause can also shift your thermal comfort significantly from night to night.
The most practical approach is to start at 65°F and adjust by a degree or two in either direction over a few nights. Pay attention to how quickly you fall asleep, whether you wake up during the night, and whether you feel rested in the morning. If you’re kicking off covers or waking up sweaty, go cooler. If you’re curling into a tight ball or waking up cold, go warmer. Your body will tell you when you’ve found it.