Late afternoon sun through the curtains, warming a bed

Perth Summer Nights: How to Sleep When the Bedroom Won't Cool Down

It's 11pm in December. The bedroom has been soaking up sun since lunch, the sheets feel warm to the touch, and you're lying on top of them doing maths on how many hours you've got left before the alarm.

Every Perth local knows this night. Summer is a couple of months off, so now is a good time to get the bedroom ready for it.

Why a hot room keeps you up

Falling asleep is a cooling job. As bedtime comes around, your body pushes heat out through your hands and feet, and your core temperature drops. That drop is one of the clearest signals your body uses to switch off for the night. Researchers have linked it to how fast people fall asleep.

A hot bedroom fights that. Heat has nowhere to go, so your body keeps working to shed it. Sleep studies find heat means more time awake, and less of the deep sleep and dream sleep you want. Humidity makes it worse, because sweat can't evaporate as well.

Perth nights are warming too. The Bureau of Meteorology put the average summer overnight low for 2024–25 at 18.8°C, above the long-term average of 17.7°C. On 21 January 2025 the temperature never fell below 27.2°C. That was the minimum. At night.

The number we named ourselves after

18.3°C is 65°F, the ideal sleep temperature. It sits in the middle of the 15°C to 20°C range sleep organisations point to. You won't hit it every night in a Perth summer without the aircon, and that's fine. Every degree you can take off the room helps.

Keep the heat out before it gets in

The fight starts at breakfast. A bedroom that bakes all day holds that heat in the walls, the mattress and the ceiling for hours after sunset.

  • Shut the west side. Close blinds and curtains on the western windows by lunchtime. Afternoon sun does the damage.
  • Open up once it drops. When the outside air is cooler than the inside air, open windows on both sides of the house and let the breeze pull through.
  • Swap the bedding. Put the doona away. A cotton or linen sheet breathes better than anything with polyester in it.

A warm shower helps. We know how that sounds.

It feels backwards. A review of the research on warm showers and baths before bed found that water at 40 to 42.5°C, one to two hours before lights out, helped people fall asleep faster and rate their sleep better. Ten minutes was enough.

The warm water draws blood to your hands and feet. When you step out, that heat leaves through your skin and your core cools faster than it would on its own. You're giving the cooling job a head start.

Make the air move

A fan won't lower the room temperature, but moving air helps sweat evaporate, and evaporation is how you cool down. Point it across the bed. If you run the aircon, put it on a timer so the room is cool when you get in and the unit shuts off once you're asleep.

Let your feet out from under the sheet. Hands and feet are where your body dumps heat, so give them some air.

Keep the breathing on your nose

Fans and aircon both dry the air out. Your nose warms, filters and humidifies the air on its way in. Your mouth doesn't do much of that. If you wake up in summer with a mouth like sandpaper, it may have fallen open overnight.

That's what our Nasal Strips and Mouth Tape are for. The strip gives your nose a gentle lift. The tape has a hole through the centre, so it's a reminder to keep your lips closed, not a seal. Do not use mouth tape if you cannot breathe freely through your nose. Always read the label and follow the directions for use.

Your summer checklist

  1. West blinds shut by lunch.
  2. Windows open once it's cooler outside than in.
  3. Doona away, cotton or linen on.
  4. Warm shower an hour or two before bed.
  5. Fan across the bed, feet out.
  6. Aircon on a timer, aiming for 18 to 20°C.

Start this week while the nights are still mild, so the habits are set by the time the first 40-degree day turns up. If you want the whole routine in one box, the Classic Bundle has the strips and the tape together.

Sources

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