How Are Sleeping Bags Rated? Season Ratings Explained

All sleeping bags should be advertised along with their ratings, which tell you how the sleeping bag should perform in certain conditions for a number of factors, such as temperature. For more information view our sleeping bag guide.


In January 2005 a new set of conditions were introduced by the EU to help regulate the testing standards for sleeping bags. These standards were created to bring testing procedures in line across the board and minimise differences between advertised standards and actual performance. 

There are now generally two ratings used for sleeping bags: comfort and season.

Comfort ratings – what are they?

A sleeping bag’s comfort rating will indicate the optimum temperatures at which the average male or female will feel too warm, comfortable or simply be able to survive, in the sleeping bag. 

There are few average people – some people will be more comfortable at cooler temperatures than others – and so this should be taken only as a guide. If you’re unsure go for the warmer option, as it’s much easier to cool off than it is to get warm.

Comfort ratings are shown as follows:

Upper limit – the highest temperature the average male can expect to have a comfortable night’s sleep at without too much sweating.

Comfort – the temperature at which the average adult woman can expect to have a comfortable sleep. 

Lower limit – the temperature at which the average adult male can expect to have a good night’s sleep in a curled position.

Extreme – the lowest temperature at which the average adult woman can survive. This rating comes with caution and additional consideration should be given if you plan to sleep in temperatures this low.

A wide range between the upper and lower limits is a good feature to look for, indicating an adaptable sleeping bag. If you get cold much easier than the average person, go for a sleeping bag with a higher lower limit.

Season ratings – what are they?

A season rating is used to inform buyers of the time of year a sleeping bag is most suitable for. Ratings start from season one for summer months all the way up to 5, for extreme cold temperatures. 

Season one - ideal for warm summer nights, typically 5°C or above.

Season two - cooler evenings in spring/summer, temperatures from around 0 to 5°C.

Season three – for anywhere between 0 to -5°C, a cold night but no frost.

Season four – best suited for the winter months, suitable for temperatures as low as -10°C.

Season five – for expedition style camping, suitable for temperatures often as low as -40°C. Typically found in the rucksacks of mountaineers.

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