A night of poor sleep during a heatwave can make the next day miserable and harder to cope with the heat. The good news is that a few well-chosen steps make a significant difference — and most of them are free.
Why heat disrupts sleep
Your body naturally cools itself during sleep — your core temperature drops by about 1–2°C in the first few hours. When the bedroom is too warm, this process is disrupted. The result is lighter, more fragmented sleep.
Research suggests that a bedroom temperature between 16°C and 19°C is optimal for most adults, though comfort varies. Above 24°C, most people find sleep is noticeably affected.
The most effective steps
1. Cool your bedroom before you go to bed
Don’t wait until bedtime to think about temperature. See our bedroom cooling guide for the full approach — the key is blocking heat during the day so your room is manageable by the time you sleep.
2. Take a cool shower or bath
A shower or bath at a cool-but-not-cold temperature (around 20°C) 30–60 minutes before bed helps your body lose heat through your skin. Don’t make it too cold — a sharp cold shower can actually raise your core temperature temporarily as your body compensates.
3. Choose the right bedding
- Lightweight cotton or linen sheets are far better than polyester or microfibre
- Avoid duvets entirely if the bedroom is above 22°C — a single cotton sheet is usually sufficient
- A cooling pillow or pillow cover can make a noticeable difference if you run hot in bed
4. Use a fan effectively
Position a fan to blow air across your body rather than generally around the room. Place it so you get a light, continuous breeze — this helps sweat evaporate and keeps you cool even if it doesn’t actually lower room temperature.
If the bedroom remains very warm, placing a bowl of cold water or ice in front of the fan adds a small cooling effect.
See our best fans for sleeping for quiet models that won’t keep you awake.
5. Timing matters
If you can, avoid going to bed at the hottest point of the evening. Many people find that staying up slightly later — until outside temperatures have dropped — helps considerably.
6. Keep a cool flannel or cold water bottle nearby
A damp flannel on your forehead, wrists or the back of your neck is a simple way to lower your perceived temperature.
What doesn’t work as well as you’d think
- Freezing your sheets: They warm up within minutes of contact.
- Keeping all windows open all day: This brings in hot air. See the bedroom cooling guide for the right timing.
- Cold showers immediately before bed: Can be counterproductive for some people (see above).
If you share a bed
Heat preferences vary between people. If one person runs cooler than the other, separate light sheets can help — each person controls their own cover without affecting the other.
Children and sleep in hot weather
Children — particularly younger ones — are more vulnerable to heat. The Lullaby Trust recommends keeping babies’ rooms between 16–20°C. If you’re concerned about your baby overheating, see the Lullaby Trust guidance.
Related: How to keep your bedroom cool · Best fans UK
Disclaimer: This article is for general information only. For medical advice about heat-related illness, consult the NHS website or your GP. For official heatwave warnings, visit the Met Office.