WELLBEING & HEALTH SERIES

How room temperature affects your sleep

You can do everything else right — but if your bedroom is a few degrees too warm, your sleep still suffers. Here's the science, and how to find your own perfect sleep temperature.

What the research shows

The numbers behind a cooler bedroom

~18°C

The widely recommended sweet spot

Sleep scientists generally point to a cool room of around 18°C for most adults — cool enough to support your body's natural overnight temperature dip. Source 1: Journal of Physiological Anthropology

14 min

Lost on a hot night

In one of the largest sleep studies ever run — tens of thousands of people across 68 countries — nights above 30°C cost people around 14 minutes of sleep on average.Source 2: One Earth.

Less deep & REM

Heat hits the best stages

When a room is too warm, you wake more often and lose slow-wave (deep) and REM sleep — the stages that repair the body and support memory and mood.Source 1: Journal of Physiological Anthropology

10 min faster

The warm-bath effect

A warm bath or shower of 40–42.5°C, taken 1–2 hours before bed for as little as 10 minutes, helped people fall asleep sooner and sleep more soundly.Source 3: Sleep Medicine Reviews

Why it matters

Your body has to cool down to fall asleep

In the couple of hours before bed, your core body temperature naturally begins to drop — and that drop is one of the key signals that tells your brain it's time to rest. A cool room helps this along. A warm one works against it, increasing night-time waking and trimming the deep and REM sleep that leave you feeling restored. Source 1: Journal of Physiological Anthropology

Bedroom temperature	How it feels	What happens to your sleep
Below 15°C	Too cold	Shivering and cold extremities make it harder to drift off and can fragment sleep through the night
15–16°C	A touch cool	Close to ideal for many, though a fraction cold for some — a pre-warmed bed helps you settle
16–19°C	The sweet spot	Supports your body's natural overnight temperature dip — the range most sleep researchers point to for adults
20–23°C	Comfortable, warming	Fine for many (and often ideal for older adults), but deep and REM sleep start to slip as you climb higher
24–26°C	Getting too warm	More night-time waking and less restorative sleep — the odds of getting under seven hours begin to rise
Above 30°C	Too hot	Sleep suffers most here — on nights above 30°C people lose around 14 minutes of sleep on average Source 2: One Earth.

A general guide for healthy adults, not a medical tool.

The mechanism

Your core body temperature: a built-in sleep thermostat

The reason a cool room helps so much comes down to what's happening inside you. Your core body temperature — the temperature deep in your body — isn't fixed. It rises and falls on a roughly 24-hour rhythm set by your internal clock, and that rhythm quietly choreographs your night. Source 5: Journal of Neuroscience.

Slide Right

Deep (slow-wave) sleep REM sleep

Evening: the cool-down begins

Your temperature peaks in the late afternoon, then starts falling a couple of hours before bed as your body releases heat through the skin — which is why your hands and feet feel warm at bedtime. You actually fall asleep on this downslope.Source 5: Journal of Neuroscience.

Overnight: the deep dip

Through the night your core temperature keeps drifting down — by roughly 1°C in total — reaching its lowest point (the nadir) in the early hours, a couple of hours before you wake. Your drive for sleep, including REM, peaks right around this low point.Source 5: Journal of Neuroscience.

Sleep cycles ride the curve

You move through roughly 90-minute cycles all night. Deep, restorative slow-wave sleep dominates the early cycles while temperature is falling fastest; REM stretches longer toward morning, clustering near the temperature nadir.Source 5: Journal of Neuroscience.

Here's the catch

A warm room blunts this whole process. If the air around you is too hot, your body can't shed heat efficiently, the natural dip is flattened, and you spend more of the night awake or in lighter sleep — losing exactly the deep and REM stages this curve is designed to deliver.Source 1: Journal of Physiological Anthropology A cool bedroom simply lets the curve do its job.

For couples

One of you runs hot, the other runs cold?

Mismatched temperature preferences are one of the number one causes of disrupted sleep for couples — one partner kicks the covers off while the other quietly hogs the blanket. The usual fixes (separate quilts, piling blankets on one side, fighting over the thermostat) are either impractical or look untidy.

Cooler side

Lighter fill

For the partner who sleeps warm

Warmer side

Heavier fill

For the partner who sleeps cold

One quilt, two warmth zones

Our Dual Warmth Quilts solve it with an elegantly simple idea: a single quilt with two different warmth levels built in. One half has a heavier fill for the cold sleeper, the other a lighter fill for the hot sleeper — so you each get your own comfort without compromise.

Looks and feels like a normal single quilt — the difference is invisible, with no seam down the middle
Choose from Tencel, Ingeo corn fibre or pure alpaca — all naturally breathable and hypoallergenic
No more "she's cold, he's hot" — and no more nightly tug-of-war over the covers

Shop Dual Warmth Quilts

Sleep Hack

Warm up to cool down

It sounds backwards, but warming your skin before bed actually helps your core temperature fall — the exact drop that ushers in sleep. Warming your hands and feet does the same thing: cosy extremities help the rest of you cool down for deeper rest.Source 4: Brain

Take a warm shower or bath 1–2 hours before bed
Aim for a cool room — around 18°C
Choose breathable bedding that lets heat escape
In summer, close blinds by day to keep heat out
In winter, warm the bed first — then let your body settle

Build your sleep climate

Simple ways to get the temperature right

A few well-chosen pieces make a cool, comfortable bed effortless — whatever the season throws at an Australian bedroom.

For the heat

Cooling Gel Pillows

A cooler surface for your head, where most of us feel the heat first. Gel-infused memory foam in contoured and classic profiles.

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Warm nights

Summer Quilts

Lightweight, breathable fills (100–300 GSM) that let heat and moisture escape instead of trapping it around you.

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The base layer

Cooling Mattress Protectors

Breathable bamboo and Tencel protectors keep the surface you lie on cooler and drier — without the clammy feel of older waterproof styles.

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Cold nights

Electric Blankets

Take the chill off so you drift off warm, then let your body settle into its natural overnight dip. Multi-zone, machine-washable options.

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A cooler room, a brighter you

When you sleep deeply and wake genuinely rested, everything downstream gets easier — sharper focus, steadier mood, and more energy for the people and things you love. You don't need to overhaul your life. Just nudge the dial a few degrees and let your body do what it's beautifully designed to do.

Explore the full range

Need a hand? Not sure where to start?

Our team helps Australians build the right sleep set-up every day — including NDIS orders. We're happy to talk it through.

Speak to an Expert

Scientific References

Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology. 2012;31:14.
Minor K, Bjerre-Nielsen A, Jonasdottir SS, Lehmann S, Obradovich N. Rising temperatures erode human sleep globally. One Earth. 2022;5(5):534–549.
Haghayegh S, Khoshnevis S, Smolensky MH, Diller KR, Castriotta RJ. Before-bedtime passive body heating by warm shower or bath to improve sleep: a systematic review and meta-analysis. Sleep Medicine Reviews. 2019;46:124–135.
Raymann RJEM, Swaab DF, Van Someren EJW. Skin deep: enhanced sleep depth by cutaneous temperature manipulation. Brain. 2008;131(2):500–513.
Dijk DJ, Czeisler CA. Contribution of the circadian pacemaker and the sleep homeostat to sleep propensity, sleep structure, electroencephalographic slow waves, and sleep spindle activity in humans. Journal of Neuroscience. 1995;15(5):3526–3538.

This article is for general education and wellbeing and isn't a substitute for medical advice. Individual needs vary — babies, older adults and people with certain health conditions may sleep best at different temperatures. If sleep problems persist, please speak with your GP.

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