Quick Answer: Research consistently points to 15–19°C (60–67°F) as the ideal bedroom temperature for sleep, cool enough to trigger the drop in core body temperature your brain needs to initiate deep sleep. Most Canadians sleep too warm. A cooler room, breathable bedding, and the right mattress material all contribute.
7 min read
This is one of those topics where the science is fairly settled and the practical advice is surprisingly simple. Most people sleep too warm. The fix isn't complicated, but it does require understanding what your body is actually trying to do when you fall asleep, and what gets in the way.
Why Sleep Temperature Matters
Your body temperature isn't constant throughout the day. It peaks in the late afternoon, around 4–6 p.m., and then begins falling in the evening. This drop in core body temperature is one of the key signals your brain uses to initiate sleep. When your environment is too warm, your body can't shed heat efficiently, and sleep onset is delayed or disrupted.
The Thermoregulation-Sleep Connection
Research published in the Journal of Physiological Anthropology found that the body must shed heat from the extremities (hands, feet, face) to lower core temperature, which is why warm feet can paradoxically help you fall asleep, they dilate blood vessels to release heat. A 2012 review in Sleep Medicine Reviews identified ambient bedroom temperature as one of the most significant environmental factors affecting sleep architecture, particularly slow-wave deep sleep (N3) and REM sleep. The Canadian Sleep Society notes that thermal comfort is a key component of sleep hygiene, especially for older adults, whose thermoregulation becomes less efficient with age. A too-warm bedroom specifically suppresses REM sleep, which is when memory consolidation and emotional regulation occur.
The Ideal Temperature Range
Most sleep researchers cite 15–19°C (60–67°F) as the target range for bedroom temperature. Within that band, individual preference matters, some people sleep better at 16°C, others at 19°C. The sweet spot for most adults is closer to 18°C (65°F).
| Bedroom Temp | Effect on Sleep | What You'll Notice |
|---|---|---|
| Below 15°C (59°F) | Possible sleep disruption | Shivering, increased wakefulness, difficulty relaxing |
| 15–17°C (60–63°F) | Optimal for most people | Faster sleep onset, deeper slow-wave sleep |
| 17–19°C (63–66°F) | Optimal for most people | Comfortable baseline; still within the ideal range |
| 20–22°C (68–72°F) | Mildly disruptive | More restless, lighter sleep, increased night waking |
| Above 24°C (75°F) | Significantly disruptive | Suppressed REM, frequent waking, feeling unrested |
Does Age Change the Ideal Temperature?
Yes, slightly. Infants and young children generally sleep better at slightly warmer temperatures, around 18–20°C, because they're less able to regulate their own temperature. Older adults often need a slightly warmer room as well, as their thermoregulatory efficiency declines. For most adults between 20 and 65, 16–19°C is the target.
What About Partners with Different Preferences?
This is one of the most common sleep conflicts in couples. Someone runs warm; their partner is always cold. A few practical solutions: separate duvets (very common in Scandinavian countries and increasingly popular in Canada), different mattress zones on a split king, or a bedside fan for the warm sleeper while the cold sleeper adds a blanket layer. The room temperature itself is a middle-ground compromise, 18°C with an extra blanket for the cold sleeper is often easier than two people disagreeing on thermostat settings.
Sleeping in Canada: Seasonal Challenges
Ontario Winters, Ontario Summers
In Brantford and across Southern Ontario, seasonal temperature extremes create two distinct sleep problems. Winter: furnace-heated homes run dry and often too warm at night, many people set their thermostat for daytime comfort and forget it doesn't drop overnight. A programmable or smart thermostat set to drop to 17–18°C between 9 p.m. and 7 a.m. makes a noticeable difference. Summer: humid Southern Ontario nights can push bedroom temperatures above 24°C, especially in homes without central air. A box fan pulling cool outdoor air in at night (when outdoor temps drop), a ceiling fan, or a window AC unit for the bedroom are the main solutions. According to Statistics Canada, approximately 45% of Ontario homes lacked central air conditioning as of 2022, a significant share of Ontarians dealing with hot summer sleep conditions.
Humidity compounds the temperature problem. At 25°C with 70% humidity, your body has difficulty evaporating sweat efficiently, which makes the room feel significantly warmer. Southern Ontario summers regularly hit those conditions. The effective solution in those cases isn't just cooling, it's dehumidifying as well. A portable dehumidifier in the bedroom (keeping relative humidity between 40–60%) combined with a fan or AC makes sleeping in hot weather substantially more comfortable.
How Your Mattress Affects Sleep Temperature
Your mattress is in direct contact with your body all night. It traps or releases heat depending on its construction, and this has a real effect on how warm or cool you sleep.
| Mattress Type | Heat Retention | Who It Suits |
|---|---|---|
| Dense memory foam (traditional) | High, absorbs and traps body heat | Cold sleepers, cool climates |
| Gel-infused memory foam | Moderate, gel draws heat away, some dispersal | Average sleepers; not enough for warm sleepers |
| Open-cell foam / latex | Lower, better airflow through structure | Average to warm sleepers |
| Innerspring / pocketed coil | Low, coil structure allows airflow | Warm sleepers, hot climates |
| Hybrid (foam + coil) | Moderate-low, combines support and airflow | Most sleepers; balances comfort and cooling |
Warm Sleeper? Here's What We Recommend
- Avoid dense memory foam: Traditional memory foam is notorious for trapping heat. If you wake up sweaty, your mattress may be the culprit as much as your room temperature.
- Pocketed coil mattresses breathe best: The air channels between coils allow heat to dissipate. Our Restonic ComfortCare uses 1,222 individually pocketed coils and stays noticeably cooler than foam alternatives.
- Sleep In flippable mattresses: The Sleep In line is a Canadian-made foam and coil flippable mattress. One side is firmer, one softer, and the open construction runs cooler than solid foam blocks.
- Breathable bedding matters too: Cotton, bamboo, and linen sheets wick moisture and allow airflow better than polyester. A mattress protector that traps heat can undo an otherwise well-designed mattress.
In our experience at Mattress Miracle, warm sleepers often don't realize their mattress is contributing to their problem until they try a different one in our showroom. The difference between sleeping on a dense foam mattress and a pocketed coil hybrid on a warm night is significant. It's one of the most common things customers mention after switching.
Practical Ways to Control Your Sleep Temperature
Room-Level Controls
- Smart or programmable thermostat: Set it to drop 2–3°C at bedtime. The difference between sleeping at 20°C and 17°C is often the difference between restless and restful. Many smart thermostats allow "sleep mode" scheduling.
- Ceiling fan or bedside fan: Moving air increases evaporative cooling from your skin, making the room feel 2–3°C cooler without actually reducing the temperature.
- Window management: In summer, close windows and blinds during the day to block heat gain. Open windows in the evening once outdoor temperatures drop below room temperature.
Bed-Level Controls
- Layer bedding instead of using one thick duvet: Layering lets you adjust easily. A light duvet plus a blanket is easier to manage than a single heavy comforter you can't fine-tune.
- Cooling mattress topper: Gel-infused or breathable foam toppers can moderate heat retention from an older or denser mattress beneath them.
- Keep feet uncovered: Exposing your feet to cooler air helps release heat quickly, which is why many people unconsciously stick a foot out from under the covers.
Body-Level Controls
- Shower before bed: A warm shower 1–2 hours before sleep raises skin temperature briefly, then causes it to drop more sharply, which helps trigger sleep. A cool shower right at bedtime has a similar effect through direct cooling.
- Avoid alcohol before bed: Alcohol raises body temperature and suppresses REM sleep, a double hit to sleep quality in warm weather.
- Light, breathable sleepwear: Loose cotton or moisture-wicking fabrics. Sleeping without clothes is also effective for temperature regulation.
Frequently Asked Questions
What is the best temperature to sleep at in Canada?
The research-supported range is 15–19°C (60–67°F), with most adults finding 17–18°C most comfortable. In Canada, the challenge varies by season, over-heated homes in winter and humid nights in summer both push bedroom temperatures too high. A programmable thermostat set to drop overnight, combined with appropriate bedding and a breathable mattress, is the most effective combination.
Why do I sleep better when it's cold?
Because your body needs to drop its core temperature to initiate and maintain deep sleep. A cooler room helps this process along. When your bedroom is too warm, your body can't shed heat as easily, which delays sleep onset and reduces deep (N3) and REM sleep stages. This is why many people report sleeping better in autumn than summer, and better in hotels with air conditioning than at home without it.
Is sleeping in a cold room bad for you?
Below about 15°C, cold can become disruptive, shivering and vasoconstriction can interfere with sleep. For most healthy adults, the range of 15–19°C is optimal. Elderly individuals, young children, and anyone with certain medical conditions (Raynaud's disease, for example) may need a slightly warmer environment. Consult your doctor if you have specific health concerns about temperature and sleep.
Does my mattress make me sleep warmer?
Yes, significantly. Dense memory foam is the worst offender, it absorbs and retains body heat through the night. Pocketed coil innerspring and hybrid mattresses allow heat to dissipate through the air channels in their coil layer. If you regularly wake up sweaty or overheated, your mattress is likely contributing. Come into Mattress Miracle in Brantford and try both, the temperature difference between lying on a foam mattress and a coil mattress is noticeable even in-store.
My partner and I disagree on bedroom temperature. What can we do?
Set the room at the cooler partner's threshold (around 18°C), and have the warmer sleeper use lighter bedding. Separate duvets, each person has their own, are increasingly common in Canadian homes and remove most bed-temperature conflicts entirely. A bedside fan directed at the warm sleeper while the other uses a heavier blanket is another practical solution that doesn't require thermostat negotiations.
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We are a family-owned mattress store in Brantford, helping our community sleep better since 1997. If you run warm at night, come try our Restonic pocketed coil and hybrid options in person. Honest advice, no pressure.
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