Practical explainer
Sleeping Comfortably During Intense Summer Heatwaves
A hot night can leave you turning the pillow over, throwing off the covers and wondering whether sleep will happen. During a heatwave, start with a more important question: can you stay safely cool where you plan to sleep? Shading, lighter bedding and a cool shower may help, but they cannot make every overheated home safe. If cooling is inadequate, arrange a cooler place rather than trying to sleep through dangerous heat. [1]
This guide focuses on adults during unusually hot weather. For everyday thermostat choices, see MySleepCure’s Ideal Bedroom Temperature article. Here, the priority is reducing heat exposure, then making rest more comfortable.
Start cooling the room before bedtime
Close blinds or curtains on sun-facing windows before the room heats up. When outdoors is hotter than indoors, keep windows closed; open them when outside air becomes cooler, provided security and air quality allow. Darkness alone does not mean the outdoor air is cooler. A simple indoor thermometer, if you have one, helps you judge conditions rather than relying on the weather forecast alone. [2]
Reduce unnecessary heat inside: switch off unused lights and electronics and avoid running the oven during the hottest part of the day. If another room stays cooler, consider sleeping there temporarily. A lower floor may be cooler than a top-floor bedroom, but check the actual conditions and choose somewhere accessible and safe. These changes can help without requiring new bedding or expensive equipment. [2]
Fans help in some conditions but have limits
A fan moves air; it does not lower the room’s air temperature. Its cooling effect depends on conditions, including temperature, humidity and your ability to sweat. Feeling a breeze is not proof that your body is cooling adequately. [1, 3]
Public-health agencies publish different temperature cutoffs for fans. CDC advises using them only below 90°F, approximately 32°C; UK guidance uses 35°C, while WHO uses 40°C. These numbers should not be treated as interchangeable guarantees of safety. Follow your local heat guidance and take a more cautious approach if you are vulnerable to heat. In extreme indoor heat, do not rely on a fan alone: use effective air conditioning or move somewhere cooler. [1, 2, 3]
If you have air conditioning, use it to maintain a safe, comfortable room rather than chasing a particular sleep-temperature target. Keep the unit’s airflow unobstructed and follow its operating instructions. Do not switch off necessary cooling simply to follow a bedtime routine.
Make the bed lighter and cool your skin
Use lightweight, loose sleepwear and remove heavy bed layers. You may be more comfortable with a light sheet instead of a comforter, duvet or doona. Choose from what you already own; a branded cooling product is not required. Separate bed covers can let partners adjust their own warmth. [3]
A cool shower or a cool damp cloth on your skin can provide relief before bed. Keep water away from plugs, chargers and fans. Do not drape wet fabric over electrical equipment or soak the mattress. Change damp sleepwear or sheets if they become uncomfortable. These are comfort measures, not substitutes for moving out of dangerous heat. [3]
Drink regularly without overcorrecting
Keep drinking water during the day and have some available overnight. Do not intentionally dehydrate yourself to avoid a bathroom trip, but do not force large volumes of water either. If you have a prescribed fluid limit, heart failure, kidney disease or another condition affecting fluid balance, ask your clinician how your plan should change during hot weather. Do not change fluid restrictions or medication doses on your own. [1, 4]
Alcohol is a poor bedtime cooling strategy. It can affect heat awareness and hydration, and although it may initially make you sleepy, it can disrupt later sleep. Avoid using it to get through an uncomfortable night. [4, 5]
Have a backup when home cooling is not enough
Before evening, identify a cooler place you could reach: a relative’s home, a cooling center or another air-conditioned public space. Check opening hours and transport; a library that closes at sunset does not solve an overnight problem. Ask your local health department or council about cooling locations and assistance if cost, mobility or access is a barrier. [1, 2]
If wildfire smoke is present, opening windows may introduce unhealthy air. Check local air-quality advice as well as heat warnings. When you cannot keep a closed home cool, seek a location offering both cooling and cleaner air rather than remaining inside an increasingly hot room. Follow evacuation instructions if issued. [6]
Make a plan if heat affects you more easily
Older adults, pregnant people and adults with certain chronic conditions need extra precautions. Some medicines affect sweating, thirst or fluid balance, including some antihistamines used as sleep aids. A clinician or pharmacist can review your medicines and help plan for hot days; stopping them without advice can create other risks. [1, 4]
Arrange a check-in if you live alone or may have difficulty recognizing or responding to overheating. Plan for power-dependent medical equipment and medicines requiring refrigeration before an outage, and keep important contact details accessible. [4]
Recognize when this is more than poor sleep
Headache, dizziness, nausea, unusual weakness or heavy sweating can signal heat exhaustion. Stop what you are doing, move somewhere cool and cool your skin. Sip water if you are fully alert and can swallow safely. Seek medical advice promptly if symptoms are difficult to manage, worsening or not settling. [7]
Confusion, collapse, a seizure or loss of consciousness during heat exposure requires emergency help. Call local emergency services immediately and begin cooling while help is on the way. Do not give drinks to someone who is confused, unconscious or unable to swallow safely. Do not wait until morning or assume they simply need sleep. [7, 8]
Give yourself a realistic night
Once you are safely cool, keep the evening simple: dim lighting, a quiet activity and a familiar bedtime routine. Avoid adding late caffeine to compensate for the previous night. If you wake feeling hot, reassess the room and your symptoms before trying another relaxation exercise. [5]
The next day, review what would make the following night safer and easier. More effective daytime shading, a cooler sleeping room or an overnight backup may matter more than another sleep trick. You do not have to achieve perfect sleep during a heatwave. The goal is safe cooling and the best rest your circumstances allow.
Sources and further reading
Official guidance checked October 31 2026. This is a practical guidance review, not a systematic review of cooling products or clinical trials.
1. CDC. About Heat and Your Health
2. UK Health Security Agency. Beat the heat keep cool at home checklist
3. World Health Organization. Heat and health
4. CDC. Heat and Medications Guidance for Clinicians
5. NHLBI. Insomnia Treatment healthy sleep habits
6. US Environmental Protection Agency. Frequent Questions About Wildland Fire Smoke for Individuals
7. NHS. Heat exhaustion and heatstroke
8. CDC. Heat Related Illnesses What to Look For and What to Do