Article on sleeping bag temperature ratings

The Secret to Sleeping Bag Ratings

The Secret to Sleeping Bag Temperature Ratings

Posted by Gav Grayston.
First Published Apr 2015; updated May 2023.

Are you confused by Sleeping Bag Temperature ratings? Not sure what the Sleeping Bag seasons are? Read our guide to avoid getting the wrong bag and getting cold at night.

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 makes buying your family a sleeping bag a little confusing, and getting the wrong one could mean cold nights in the tent.

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

Sleeping Bag Rating

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 needing 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.

The sleeping bag will feel very cold if the temperature reaches or falls below the Lower Limit.

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.

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, the bag will be too hot if it is warmer than this temperature.


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.


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 to the actual seasons.

Here's our guide to sleeping bag seasons.

1-Season Sleeping Bags

10 °C or higher - Warm Summer Nights Only

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 you may not even sleep in it. A warmer bag would be too hot in those conditions.

2-Season Sleeping Bags

5 °C or higher - Cooler Nights

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.

If your family only camps in Summer and perhaps late Easter, then a 2 Season Bag is usually sufficient.

However, invest in a 3-Season sleeping bag if someone feels cold at night.

3-Season Sleeping Bags

0 °C or higher - Cold Nights but not Frosty

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 Sleeping Bags

-5 °C or higher - Frost and Snow

Winter bags are suitable for very cold Winter nights down to -10 degrees.

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 only good on warm summer nights.

In the UK, we can't guarantee warm summer nights every night. If you are only taking your family camping in the summer, we recommend getting 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, 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 much more space when packed, so check you have enough space in your car.

What about sleeping bags for children?

Sleeping Bags for Kids

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 typically a 1-Season. They are fine for sleepovers at their friend's house or if you are camping out when it's warm and dry in the summer.

'Proper' kids sleeping bags are usually 2-Season.

You can take measures to ensure 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, print out our quick guide below and take it to the camping shop.

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

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

A quick guide to choosing a sleeping bag