Are you waking up sweaty at 2 am, kicking off the doona, and then lying awake feeling oddly cold? If so, then your bedroom may be working against you. For health-conscious Australians, especially those training, recovering from injury, managing illness, or dealing with hormonal shifts, bedroom temperature sleep is one part of a personalised setting, not a guarantee against waking overnight.
Your ideal sleeping temperature varies with bedding, clothing, age, health, hormones, humidity, and climate. As your body regulates its heat before sleep, the ambient temperature around you matters too, not just the thermostat display. A few practical changes can make the room temperature more comfortable for sleep. Let’s explore more.
Table of contents
- Bedroom Temperature Sleep: Start at 18C
- Your Body Cools Down Before You Sleep
- What Happens When Your Room Is Too Hot or Too Cold?
- Temperature Needs Change With Age and Health
- Humidity, Bedding and Uneven Room Temperatures
- Use Your Evening Routine to Help Cooling
- Frequently Asked Questions
- Key Takeaways: A Cooler-Night Conclusion
Bedroom Temperature Sleep: Start at 18C
For most healthy adults, a bedroom temperature between 15.5°C and 19.5°C is a sensible starting range. Many people often find that 18°C suits them, but it isn’t a universal rule. Bedding, humidity, medication, body size, hormones, and where you live all affect sleep comfort.
Treat this as a personal experiment, not a thermostat commandment. Set the room near 18°C for a week, then note how often you wake, whether you sweat, and whether you add blankets before dawn.
A cool room should not feel icy
You should feel pleasantly cool when you first climb into bed, then comfortable beneath light, breathable layers. Shivering, cold hands, or needing to add layers can mean you’re sleeping in an environment that’s too cold. If this is the case, then adjust your bedding or raise the room temperature slightly to see if this reduces the cold you’re feeling.
If you’re unsure of your bedroom temperature, get yourself a simple room thermometer. This approach takes the guesswork out of making slight adjustments and lets you know exactly how cool your bedroom is at any given time. It’s also important to remember that your home heating settings don’t always match the actual temperature at pillow height.
Use bedding to fine-tune the result
You can also use bedding to regulate your temperature. Keep your room cooler, then adjust your bedding to suit your requirements. Some of the best bedding to use is made from cotton, linen, bamboo viscose, or wool. These let you layer your bedding for more control, rather than using trol than one heavy synthetic doona. For instance, a light quilt plus an extra blanket at the foot of the bed works better than waking up trapped under a single heat-retaining layer.
HOT TIP: If you share a bed, use multiple layers of bedding. This lets you and your partner adjust your bedding to suit your individual sleeping needs. Plus, you can both sleep in the same room at the same temperature without fighting over the doona.
Your Body Cools Down Before You Sleep
Sleep is not a switch you can flick on or off when you need it. As the day turns to night, your circadian rhythm often lowers your core body temperature by roughly 0.5-1 °C, though the pattern varies from person to person. Blood flow increases in your hands and feet, helping heat leave the body. This thermoregulation supports drowsiness and melatonin production.
A detailed review of thermal environment and sleep examines the close link between body temperature and sleep. A warm room can make heat release harder, potentially delaying sleep and making lighter sleep more likely, though this isn’t guaranteed for everyone.
REM sleep is less forgiving of heat
As sleep stages shift into rapid eye movement, or REM sleep, your ability to regulate temperature is reduced. Why? Well, at this stage of sleep, vivid dreams often occur, and your brain starts processing emotions. While temperature can affect slow-wave sleep differently for each person, remember that a cool room doesn’t guarantee more deep sleep.
Research on body cooling and sleep supports a close biological link between temperature control and sleep regulation. A hot bedroom doesn’t guarantee a bad night, but studies suggest it may make restless, fragmented sleep more likely.
The best setting is not the coldest room possible. It is the room that lets your body cool down without leaving you shivering at 4 am.
HOT TIP: Warm feet can help you fall asleep in a cool room. Try socks or a hot water bottle for 10 minutes before bed, then remove it.
What Happens When Your Room Is Too Hot or Too Cold?
Sleeping in a room that’s too hot is common in Australia, particularly during humid summers, heatwaves, menopause, and in upstairs bedrooms. Signs of sleeping in a room that’s too hot include sweating, tossing and turning, waking up thirsty, feeling like your heart is racing, and waking repeatedly. If this occurs, you may wake the next day feeling exhausted despite having spent enough time in bed. Why? Well, your sleep quality is often worse because your core temperature is too high whilst trying to sleep.
A real-world heat and sleep study found that a 5 °C increase in average nighttime ambient temperature was associated with 23 fewer minutes of sleep. In a separate 2023 community study, temperatures rising from 25 °C to 30 °C were associated with a 5% to 10% decrease in sleep efficiency.
Cold can wake you too
A cold room can feel refreshing at bedtime, but it can become disruptive once your body temperature drops further overnight. Cold hands, muscle tension, or a stiff neck may suggest sleeping too cold; waking to add another layer is another clue. Heat and cold can disturb comfort, but neither necessarily causes night wakings.
If you train regularly, interrupted sleep can also affect how recovered you feel after a workout. It’s essential to remember that temperature alone doesn’t determine training adaptation. Your body repairs itself during deeper sleep, which is why training, rest, and recovery belong in the same conversation.
HOT TIP: Do not judge your room temperature at bedtime alone. Notice how you feel when you wake in the early morning hours, when the house is usually at its coolest.
Temperature Needs Change With Age and Health
While an 18°C bedroom is a reasonable starting point for adults, it won’t suit everyone. Age, illness, medication, hormonal changes, and sleep disorders can alter what your body needs.
Babies, toddlers, and older adults need a different starting point
Babies and toddlers are usually more comfortable in a slightly warmer room, around 18-21 °C. The Cleveland Clinic’s sleep-temperature guidance places children above the typical adult range. To assist a baby in regulating their temperature, dress them in suitable sleepwear, avoid overheating, and follow current safe-sleep advice. A room’s temperature range should never replace official infant-safety recommendations.
Older adults may also prefer a warmer temperature setting. For example, a study of older adults found that their stress responses were higher when bedroom temperatures exceeded 24 °C, while other research suggests that many older adults sleep comfortably between 20 °C and 25 °C. The older-adult temperature study is a reminder that comfort and physiology can change with age.
Menopause, illness and sleep apnoea
Hot flushes and night sweats can make sleeping in a cooler room around 20-22 °C more comfortable. To regulate your temperature during menopause, illness, or sleep apnoea, use light layers, keep water nearby, and choose sweat-wicking pajamas that dry quickly. If night sweats are new, drenching, or paired with unexplained weight loss, fever, pain, or fatigue, book a GP appointment.
Adjusting your bedroom temperature does not treat sleep apnoea. But it can help you get a more restful sleep. If you snore loudly, wake up gasping, or feel exhausted despite getting enough sleep, speak with your GP or a sleep specialist.
HOT TIP: Keep a seven-night sleep diary. Use your phone’s notes app to record room temperature, wake-ups, alcohol intake, exercise, and symptoms. Patterns appear faster than you expect, and they can give you clues on what to adjust to improve your sleep quality.
Humidity, Bedding and Uneven Room Temperatures
Temperature is only half the story. Your sleep environment also depends on humidity, airflow, light, and bedding. A room at 18°C can still feel sticky when humidity is high, or harsh when the air is too dry. Aim for a relative humidity between 30% and 50% as a practical guide for comfort and respiratory health.
High humidity slows sweat evaporation, so your body struggles to cool itself. Very dry air can irritate your nose and throat, which is especially unpleasant if you snore or use CPAP therapy.
Fix the room, not only the thermostat
If one side of your bedroom is much warmer, look for the cause. Sun-facing windows, leaking seals, blocked vents, a hot roof cavity, or air conditioning that needs servicing can all create a pocket of trapped heat.
Smart home thermostats can schedule or monitor temperatire changes. But verify their readings with a separate thermometer at pillow height. Use blackout curtains to reduce sunlight and daytime heat. A ceiling fan on low can provide gentle airflow across your body without making the room excessively cold. If you’re sleeping too hot despite a lower thermostat setting, check humidity levels, since a dehumidifier may feel more effective than lowering the air conditioning by another degree.
Let your bed breathe
Synthetic mattress protectors, foam mattresses, and thick polyester quilts can hold heat. You do not have to replace everything at once. Start with cotton or linen sheets that breathe and cool, then consider a wool underlay or waffle blankets when warmer months arrive.
Temperature is one piece of your sleep setup. AV Edge’s sleep-quality overview also puts routine, relaxation, and daily habits alongside the bedroom environment.
HOT TIP: Put the thermometer at pillow height, away from direct airflow, lamps, and windows. That number is closer to what your body experiences.
Use Your Evening Routine to Help Cooling
A warm shower before bed may sound backward, but timing matters. A comfortable shower or bath at around 40°C to 42.5°C, taken 1 to 2 hours before bed, may support cooling by warming the skin and increasing circulation. Once you get out, your body can release heat more easily.
Research suggests this approach may reduce the time to sleep onset by roughly 10 minutes for some people. Keep your shower, bath or even spa comfortable. You are cueing a cooling response, not turning your bathroom into a sauna.
Build the rest of the routine around sleep
A cool bedroom won’t cancel out a late coffee, heavy alcohol intake, bright screens before bedtime, or chronic stress. Aim for seven or more hours of sleep, the general adult recommendation, but routine changes can’t replace assessment for persistent symptoms such as loud snoring, gasping, or ongoing insomnia. Support your bedtime ritual with daytime movement, strength training, nourishing food, and sleep hygiene, including regular sleep timing, light exposure, sensible caffeine and alcohol habits, stress management, and a suitable wind-down routine.
A consistent wake time also helps set your body clock. If your mind is busy, calm it before bed with slow breathing or reading under dim light. More ideas are available in these sleep habits for a healthy mind.
HOT TIP: Use smart thermostats to pre-cool the room 60 to 90 minutes before bed, rather than blasting cold air once you are already under the covers.
Frequently Asked Questions
What is the best bedroom temperature for sleep?
For most healthy adults, 15.5°C to 19.5°C is a sensible range, with around 18°C as a practical starting point. Adjust the room temperature based on your bedding, clothing, humidity, health, and how you feel during the early morning hours.
Is it better to sleep in a cold room?
A cool room can support your body’s natural cooling process, but it shouldn’t leave you shivering or waking up with cold hands and tense muscles. Use breathable bedding and raise the temperature slightly if you keep adding layers overnight.
What should I do if I sleep too hot?
Start by checking humidity, airflow, bedding, and whether heat is entering through windows or the roof. Light layers, a fan on low, blackout curtains, and a dehumidifier may help, but persistent night sweats or symptoms such as fever and unexplained weight loss warrant a GP appointment.
Does humidity affect sleep temperature?
Yes. High humidity slows sweat evaporation and can make an 18°C room feel sticky, while very dry air may irritate your nose and throat. Aim for roughly 30% to 50% relative humidity, then adjust it to suit your comfort and respiratory needs.
Key Takeaways: A Cooler-Night Conclusion
- Start with a bedroom temperature of about 18°C. Adjust it for your bedding, age, and symptoms to find your optimal sleep temperature.
- Keep humidity near 30% to 50%, particularly during muggy weather.
- Use light, breathable layers instead of one heavy doona.
- If heat, snoring, or sweating keep waking you, look beyond the thermostat and speak with a GP if symptoms persist.
- Support your sleep with consistent hours, daily activity, stress management, and enough time in bed.
Your bedroom should make sleep easier, not give your body another job to do. A cooler, well-layered room may reduce heat-related discomfort for some people and make nights more comfortable.
HOT TIP: Change one variable at a time for a week. That is how you can develop your own sleep ritual that works for your body, not somebody else’s.
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