Last updated: August 2026
When a UK heatwave arrives, the days are glorious and the nights are miserable. A stuffy, overheated bedroom makes it hard to drop off, easy to wake, and tough to feel rested the next morning.
The good news is that a few simple changes to your room, your routine and your bedding can bring your body temperature down and help you sleep through even the warmest nights. Here is how to sleep in a heatwave, backed by the science of why heat wrecks your rest.
Quick answer: To sleep in a heatwave, keep your bedroom cool by closing curtains and windows during the day, then opening them at night once the outside air has dropped. Take a cool shower before bed, stay hydrated, and avoid alcohol and caffeine. Breathable bedding, a cooling pillow and a hybrid mattress with open-cell foam all help your body shed heat so you can nod off faster.
Why is it so hard to sleep when it is hot?
Your body is wired to cool down before sleep. In the couple of hours before bed your core temperature naturally falls, a shift that coincides with the release of the sleep hormone melatonin and helps signal that it is time to rest.
That cooling happens through a process called vasodilation, where blood flow increases to your hands and feet to release heat. When the bedroom is too warm, your body cannot offload that heat easily, so falling asleep takes longer and you wake more often through the night.
The Sleep Foundation recommends a bedroom temperature of around 18°C (65°F) for the best sleep. During a UK heatwave many bedrooms sit well above this, especially upstairs, which is exactly why summer nights feel so restless. You can see how the country sleeps in our UK Sleep Statistics 2026.
What is the best temperature for sleep?
The best bedroom temperature for sleep is around 18°C, and most people sleep well anywhere between 16 and 19°C. That is cooler than most UK bedrooms in summer, and often cooler than a heated bedroom in winter too.
A cool room does more than help you drop off. In a small study published in the journal Diabetes in 2014, healthy adults who slept in a 19°C room for a month increased their brown fat, the tissue that burns energy to make heat, and improved their insulin sensitivity; a month at 27°C reversed it. The study by Lee and colleagues was small, but it points the same way as the sleep research: cooler is better.
The same rule applies out of season. If you heat the bedroom in winter, turn the radiator down or off an hour before bed rather than sleeping in a warm room, and use the duvet to manage warmth instead. A room that is too cold is far easier to fix with bedding than a room that is too warm.
How to keep your bedroom cool in a heatwave
Getting the room temperature down is the single biggest thing you can do. Work on the space during the day so it is already cooler by bedtime.
- Close curtains and blinds on sun-facing windows during the day to block out heat, and keep windows shut while it is hotter outside than in.
- Open windows at night once the outside temperature has dropped below your bedroom temperature, to let cooler air flow through. The NHS advises closing windows during the day and opening them at night when it is cooler.
- Use a fan to move air. The NHS notes that electric fans help when the temperature is below 35°C. Placing a bowl of ice in front of the fan gives you an extra chill.
- Switch off electronics and lamps, which give off heat and add to a warm room.
- Keep internal doors open to help air circulate, but think about security before leaving windows open overnight.
How to cool your body down before bed
Once the room is as cool as you can make it, turn to your own body temperature. Small habits in the hour before bed make a real difference.
- Take a cool or lukewarm shower before bed, or run cool water over your wrists and other pulse points to bring your temperature down.
- Stay hydrated. Keep a glass of water by the bed, and avoid alcohol and caffeine, which the NHS flags as best avoided in hot weather because they disrupt sleep and add to dehydration.
- Chill your bedding. Pop your pillowcase and top sheet into the freezer in a bag for an hour before bed for a cool start to the night.
- Wear light, loose nightwear in breathable cotton, or use just a sheet rather than a heavy duvet.
- Cool your pulse points with a damp flannel on the back of the neck, or an ice pack wrapped in a tea towel on the wrists, and keep your feet outside the covers.
- Eat light and eat early. A heavy evening meal raises your body temperature as you digest it, and using the oven heats the kitchen and the rooms above it. Cold or quickly cooked food is the better choice on a hot night.
- Move your workout. Exercise in the evening raises core temperature for hours afterwards, so train in the morning during a heatwave.
The bedding that helps you sleep cool
Your mattress, pillow and protector sit right against your skin all night, so they have a big say in how hot you get. Materials that trap heat, like older solid memory foam, make a warm night worse, while breathable, moisture-wicking bedding helps heat escape.
A lot of the heat you feel builds up around your head and neck, which is why a cooling pillow is one of the easiest upgrades. The REM-Fit 500 Cool Gel Pillow, a Good Housekeeping Winner 2026, pairs a cool-gel layer with supportive memory foam to draw heat away as you sleep.
REM-Fit 500 Cool Gel Pillow
Good Housekeeping Winner 2026: a cool-gel top layer over memory foam to keep your head cool all night.
Shop the 500 Cool Gel PillowIf you prefer a moulded memory foam feel, the Snow Pillow uses a cooling cover designed for people who tend to overheat at night. You can compare the full cooling line-up in our pillows collection.
Protecting the mattress matters too. The REM-Fit Tencel Cool Mattress Protector, another Good Housekeeping Winner 2026, is made from breathable Tencel that wicks moisture and helps your mattress sleep cooler and fresher.
REM-Fit Tencel Cool Mattress Protector
Good Housekeeping Winner 2026: breathable Tencel that wicks moisture to keep your mattress cool and dry.
Shop the Tencel Cool ProtectorREM-Fit cooling range at a glance
| Product | What it does | Best for |
|---|---|---|
| 500 Cool Gel Pillow | Cool-gel layer over memory foam (GH Winner 2026) | Hot sleepers wanting a supportive, cooling pillow |
| Snow Pillow | Memory foam with a cooling cover | Those who overheat but like a moulded feel |
| Tencel Cool Protector | Breathable Tencel that wicks moisture (GH Winner 2026) | Keeping your mattress cool and fresh |
| 5000 Lux Elite Mattress | Open-cell foam plus pocket springs for airflow | The coolest whole-mattress upgrade |
Is your mattress making you hotter?
If you sleep hot every summer, the mattress itself may be the culprit. Dense, older foams hold on to body heat, so you feel like you are lying on a warm surface no matter what you do to the room.
Every mattress in our hybrid mattress collection uses open-cell memory foam, made with an open cell structure that lets air pass through the foam so heat and moisture move away from you, over tall pocket springs that leave the core mostly air. The premium REM-Fit 5000 Lux Elite Hybrid Mattress takes that furthest, with the highest spring count in the range and the deepest open-cell layer, which is why Good Housekeeping's reviewers singled out its cooling. Our guide to the best cooling mattress in the UK explains what to look for.
REM-Fit 5000 Lux Elite Hybrid Mattress
Breathable open-cell foam and pocket springs work together to keep you cool through the warmest nights.
Shop the 5000 Lux Elite✓ 100-night trial (200 with a protector)✓ 15-year guarantee✓ Free UK delivery✓ 0% finance
Frequently asked questions
Last updated: August 2026
What is the best temperature to sleep in?
The Sleep Foundation recommends a bedroom temperature of around 18°C (65°F) for most people. A cooler room supports the natural drop in your core body temperature that helps you fall and stay asleep.
Do fans help you sleep in a heatwave?
Yes, a fan helps by keeping air moving so sweat can evaporate and cool your skin. The NHS notes that electric fans are useful when the temperature is below 35°C, and setting a bowl of ice in front of one adds an extra cooling effect.
Should I sleep with the window open in a heatwave?
Keep windows closed during the day when it is hotter outside than in, then open them at night once the outside air has cooled. This stops hot air pouring in by day and lets cooler air circulate while you sleep.
What should I wear to bed in hot weather?
Light, loose nightwear in a breathable fabric like cotton is ideal, as it lets air move and absorbs moisture. Some people sleep better with just a sheet rather than pyjamas or a duvet.
Why can I not sleep when it is hot?
Your body needs to lower its core temperature to fall asleep, and a hot bedroom makes that harder. When you cannot shed heat, it takes longer to drop off and you wake more often, which is why heatwave nights feel so restless.
Is it healthier to sleep in a cold room?
A cool room, around 16 to 19°C, is healthier than a warm one because it supports the drop in core temperature that triggers sleep. A 2014 study found a month of sleeping at 19°C increased brown fat and improved insulin sensitivity in healthy adults. A room cold enough to make you shiver is not better; add a layer instead.
Does a cooling mattress make a difference in a heatwave?
Yes, if the cooling comes from the build rather than just the cover. Open-cell memory foam lets air pass through the foam and a pocket spring core is mostly air, so heat moves away from you instead of building up underneath. A cold-touch cover alone stops working within minutes.
Sleep cool, all summer long
You cannot control the weather, but you can control your bedroom. Cool the room during the day, cool your body before bed, and choose breathable bedding that works with your natural temperature drop rather than against it.
With the right pillow, protector and mattress, even a UK heatwave does not have to cost you a good night's sleep.
