The Secret to Sleeping Bag Temperature Ratings

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The first time you buy your family sleeping bags you can be forgiven for feeling confused by all the temperature ratings. You’ll find Upper Limits, Comfort Ratings, Lower Limits, Extreme Temperatures, 1 Season, 2 Season, and so on.

getting the wrong sleeping bag could mean cold nights in the tent

These ratings are there for a reason, but it does make buying your family a sleeping bag a little confusing, and getting the wrong sleeping bag could mean cold nights in the tent.

We help demystify things to help you choose the right sleeping bags for your family.

Which Sleeping Bag Temperature Rating?

The temperature ratings that come with sleeping bags are a rough guide. The best guide to look at is the Comfort temperature.

The Comfort level is the temperature that the sleeping bag should be comfortable without the need for any additional blankets.

If a sleeping bag has an Upper Limit, that will be the temperature when you will start to feel a bit warm in it.

If the temperature reaches or falls below the Lower Limit, the sleeping bag will start to feel very cold.

Ignore the Extreme temperature. The sleeping bag will not be usable at this temperature. This is the temperature when you are likely to get hypothermia!

Sleeping Bag Temperature Ratings Explained

Sleeping bag temperature ratings are just a guide, and what feels warm to one person may feel different to another. Remember that kids can get hotter and colder quicker than adults.

Rating	Description
Upper Limit	This is supposed to be the temperature that a ‘standard man’ would be comfortable without sweating, with arms outside the bag and the bag unzipped. I say ‘supposed’ as all of us are slightly different – a ‘standard man’ is supposed to be a 25-year-old weighing 73kg and is 1.73m high….that’s not me 😉 In other words, if it is any warmer than this temperature, then the bag will be too hot.
Comfort	This is the temperature a ‘standard woman’ (again, this might not be you) can expect to sleep comfortably.
Lower Limit	The temperature that a ‘standard man’ (so perhaps a slightly lower limit than a ‘standard woman’) can sleep for 8 hours in a curled position without waking.
Extreme	The minimum temperature to use the sleeping bag by a ‘standard woman’ for six hours without dying from hypothermia….though some frostbite is still possible (oh, great!). This is the emergency-last-resort-temperature.

What are Sleeping Bag Seasons?

As well as temperature ratings the sleeping bags are put into ‘seasons’ to help make it easier to choose the right bag.

Unfortunately, the sleeping bag seasons don’t nicely map on to the actual seasons.

Here’s our guide to sleeping bag seasons.

Season	Weather	Typical Night Temperature	Description
1 Season	Warm Summer Nights Only	10 °C or higher	Best for Summer only and may be rated for the coldest temperatures of about +4 to +5 degrees. A lot of kids sleeping bags are Summer only. If you’re summer camping in Europe, then a 1 Season bag is ideal…and in fact, you may not even sleep in it. A warmer bag would be too hot in those conditions.
2 Season	Cooler Nights	5 °C or higher	Ideal from Late Spring through to Early Autumn. For most UK family campers, a 2 Season bag is adequate (along with some other measures to keeping warm in the cooler months). You would not want the temperature to get close to zero.
3 Season	Cold Nights but not Frosty	0 °C or higher	If Spring and Autumn camping is what you are doing, then go for a 3 Season bag. Most of these sleeping bags will keep you warm on cold nights and not too hot on milder nights (though you might need to have it unzipped). Their lower limit may be rated from zero to -5 degrees, but you will start to feel the cold then.
4 Season	Frost and Snow	-5 °C or higher	Winter bags that are suitable for very cold Winter nights down to -10 degrees. If you are interested in a sleeping bag for winter, read our guide by clicking here.

We added the temperature rating to the table above to give you a good idea of what sort of temperature each sleeping bag season is best for.

Which Sleeping Bag Season should you buy?

if you are only taking your family camping in the summer you should get a 2 Season sleeping bag

The 1 Season sleeping bags are cheaper, but they are only good on warm summer nights.

In the UK we can’t guarantee warm summer nights every night. We recommend if you are only taking your family camping in the summer you should get a 2 Season sleeping bag.

If you want to start camping a little earlier, such as the May school half term, or a little later into September, then get a 3 Season sleeping bag.

If someone in your family feels the cold, a 4 Season sleeping bag would be a better option.

Unless you get a very expensive backpacking sleeping bag, a 4 Season sleeping bag will take up a lot more space when packed, so check you have enough space in your car.

What about sleeping bags for children?

There are a lot of cheap sleeping bags for kids, usually with printed characters on, that don’t display any temperature ratings at all.

This type of sleeping bag is a 1 Season. They are fine for sleepovers at their friend’s house, or if you are just camping out when it’s warm and dry in the summer.

‘Proper’ kids sleeping bags are usually 2 Season.

There are measures you can take though to make sure your children stay warm during the night. Click here to read our guide to setting up your sleeping area properly.

You can also buy a sleeping bag thermal liner if you are camping on the odd occasion when the weather is colder without having to buy a whole set of new sleeping bags.

A Quick Guide to Choosing a Sleeping Bag

If you think you won’t remember which rating to look at when choosing sleeping bags, then print out our quick guide below and take it with you to the camping shop.

Beware of some shops selling sleeping bags that look warm but are not rated for cooler nights.

Also, avoid being sold really expensive backpacking sleeping bags if you don’t need it and are just camping with your car.