A summer duvet is a duvet rated 4.5 tog or lower. For most UK summer nights, 4.5 tog is the right weight. 2.5 tog suits warm spells, and 1 tog suits heatwaves, when the bedroom stays hot all night. 7.5 tog is too warm for summer for most adults, and 9 tog is warmer still. This guide shows how warm UK summer nights get, when to go lighter, whether 4.5 tog works in spring, and how to keep cool on hot nights.
Here's which tog to choose by the night and the bedroom:
| Night | Your bedroom overnight | Tog |
|---|---|---|
| Heatwave or tropical night | Hot all night, outside stays above 20°C | 1 tog |
| Warm spell | Stays above 18°C until morning | 2.5 tog |
| Typical summer night | Warm at bedtime, cools towards 18°C by morning | 4.5 tog |
| Cool summer night, north-facing room | Holds 16 to 18°C or a little below | 4.5 or 7.5 tog |
| Spring and early autumn | Drops below 16°C by morning | 7.5 to 10.5 tog |
The tog bands follow the usual UK comfort ranges for adults: 1 to 2.5 tog minimal, 3 to 4.5 tog summer and 7.5 to 10.5 tog spring and autumn. 16 to 18°C is The Sleep Charity's recommended bedroom temperature, and a tropical night is the Met Office's term for a night that doesn't fall below 20°C.
How warm are UK summer nights?
UK summer nights are cool by the numbers: the Met Office's 1991 to 2020 averages put the typical night-time low at 9.1°C in June and 11.0°C in July and August across the UK. England runs a little warmer, at 11.8°C in July and August.
Those are outdoor lows, and a bedroom that has had sun on it all day is usually warmer than the air outside. The averages also hide the hot spells. The Met Office says tropical nights are becoming more frequent in the UK, particularly during heatwaves, and in July 2022 the UK had 3 in a row.
Is 4.5 tog cool enough for summer?
Yes, 4.5 tog is cool enough for most UK summer nights. It sits at the top of the summer band of 3 to 4.5 tog, which suits a bedroom that's warm at bedtime and cools overnight. If you still wake up hot under it, the room is too warm for 4.5 tog and 2.5 tog is the next step down.
4.5 tog is the one summer duvet to buy if you only want one. It covers June to August in most homes and the warmer end of late spring.
When do you need a 1 or 2.5 tog duvet?
You need 2.5 tog when the bedroom stays above 18°C all night, and 1 tog in a heatwave, when the room is still hot at 3am. Both sit in the minimal band of 1 to 2.5 tog, which is little more than a duvet cover's warmth.
A 1 tog duvet also suits hot sleepers through the whole summer, and loft rooms under a roof that holds the day's heat. If you only feel too warm on a handful of nights a year, a 4.5 tog with the window open is often enough.
Is a 7.5 tog duvet too warm for summer?
Yes, a 7.5 tog duvet is too warm for summer for most adults. It sits in the spring and autumn band of 7.5 to 10.5 tog, and summer duvets are 4.5 tog or lower. In a bedroom that stays cool in summer, such as a north-facing room, 7.5 tog can still be comfortable on cooler nights.
7.5 tog holds 67% more heat than 4.5 tog, measured as thermal resistance: 0.75 against 0.45 square metre kelvin per watt. That's the gap you feel on a warm night. Our guide on what a tog rating means explains the measurement.
Is 9 tog too hot for summer?
Yes, 9 tog is too hot for summer for most adults. It sits between 7.5 and 10.5 tog, inside the spring and autumn band, and holds twice the heat of a 4.5 tog duvet. For summer, go down to 4.5 tog or lower.
You'll mostly see 9 tog as the heavier half of an all-season set, or on children's duvets. For a child's bed, see our toddler duvet tog guide.
Is 4.5 tog enough in spring?
No, 4.5 tog isn't enough for most spring nights, because the Met Office averages put the UK night-time low at 3.8°C in April and 6.3°C in May. Spring suits 7.5 to 10.5 tog. 4.5 tog starts to work in late May and June, or in a bedroom that stays warm.
If the heating still goes off at night and the room is cold by morning, start spring on 10.5 tog and drop to 7.5 tog as the nights warm up. Our page on the 10.5 tog duvet covers when the middle weight is enough.
Why does an all-season duvet use 4.5 tog for summer?
An all-season duvet uses 4.5 tog for summer because it's 2 duvets, a 4.5 tog and a 9 tog, and the lighter one is the summer weight. Used alone, the 9 tog covers spring and autumn. Fastened together with poppers, the two make 13.5 tog for winter, because layered tog ratings add up.
So the summer half of every 4.5 plus 9 set is the same weight as a standalone summer duvet. If you already own a 10.5 tog duvet, a 4.5 tog alongside it covers the whole year without a set.
Do you need a duvet at all in a heatwave?
No, you don't need a duvet in a heatwave if you're comfortable without one. The Sleep Charity's advice for hot nights is to remove heavy blankets and use only a cotton sheet, or a duvet with a low tog rating. A 1 tog duvet is the lightest standard rating.
If you like the feel of something over you, a 1 tog duvet gives that with very little warmth, and it's easy to throw off half the bed.
How do you keep cool in bed on hot nights?
Keep cool in bed by shutting out the sun by day, letting cool air in at night and using a light duvet. Here are 7 tips from the NHS and The Sleep Charity:
- Keep windows, curtains and blinds shut during the day, as the NHS advises.
- Open windows at night once the air outside is cooler than the room.
- Use an electric fan while the room is below 35°C. The NHS gives that limit for fans.
- Open the loft hatch, if you have one, so hot air can escape, as The Sleep Charity suggests.
- Take a cool shower or bath before bed to bring your temperature down.
- Wear light cotton nightwear, which The Sleep Charity says absorbs sweat.
- Drink cold water in the evening and keep a glass by the bed. Cut back on caffeine, alcohol and large meals late in the evening.
The Sleep Charity also suggests filling a hot water bottle with ice-cold water, or chilling a pillowcase in the fridge before bed. For the full year in one chart, see our duvet tog guide for each season.
Which summer duvets do we sell?
Our lightweight duvet comes in 1, 2.5, 4.5 and 7.5 tog for summer and the months either side, and in 10.5, 13.5 and 15 tog for the colder months. The filling is hypoallergenic hollowfibre stitched in channels so it stays spread out, and it's machine washable.
| Tog | Sizes | From |
|---|---|---|
| 1 tog | Double, king | £15.99 |
| 2.5 tog | Single to super king | £16.99 |
| 4.5 tog | Single to super king | £17.99 |
| 7.5 tog | Single to super king | £18.99 |
It weighs about 1.2 kg to 2.2 kg depending on size. Allow 24 hours after unpacking for it to loft fully.
Written by the Adam Home team in the UK.
