Sleeping Bag Temperature Ratings (Season & Comfort) Explained

Man wrapped in a dark grey sleeping bag.

A Good Night’s Sleep

We all know the importance of a good night’s sleep. This is especially true when you’re enjoying an overnight outdoors experience. However picking the right sleeping bag for the season or climate can sometimes be a little confusing. For example, what does a 1 Season sleeping bag really mean?

We’re going to delve into the sleeping bag temperature ratings and the difference between Season or Comfort. Then by the end of this post hopefully you will have a better understanding and be able to pick the right bag for you.

One thing to keep in mind with any rating system is that they exist to help guide and inform you. This doesn’t mean that they are the rules. At the end of the day whatever you find most comfortable is right!

Season Rating

Sleeping bag’s season ratings are a quick way to gauge what bag is appropriate for any given time of year. Commonly rated 1-4 with higher numbers indicated a warmer sleeping bag.

So a 1 Season sleeping bag is probably only really going to be suitable for hot summer months. Makes sense! Some of the confusion around the seasons way of rating sleeping bags comes more so from 2 through 4 (and depending on brand 5).

A 4 Season sleeping bag you might think, given its name, could be used in Spring, Summer, Autumn and Winter. This is true to a degree but realistically a 4 Season sleeping bag is probably going to be too warm through Summer to use.

Comfort Ratings

The season rating may be the quickest way to narrow down a range of sleeping bags, but the comfort rating is where the real detail is.

Typically portrayed an icon with three segments, which represent:

  • Comfort
  • Limit
  • Extreme
Chart demonstrating the different comfort ratings for a sleeping bag.
Example: Comfort Icon

Inside of each segment you will normally find a temperature. This temperature is there to help demonstrate the intended use of the sleeping bag.

Similarly to the season ratings, which we looked at before, it is again not there to serve as a rule. You should always go with what is most comfortable for you, and this is something that you will discover with experience.

We would always suggest going slightly warmer than you think you will require. This is because we have found, through our own time outdoors, that its often easier to cool down than warm up again.


This is considered the lowest temperature at which an adult woman can sleep comfortably while lying on her back.


This is considered the lowest temperature at which an adult male can sleep comfortably while in a curled-up position.


This temperature comes with a caution as it is the lowest temperature that the bag should be used in by an adult woman. However its use comes with an expectation of risk to their health from hypothermia. Consider this as a worst case scenario rating.

Important To Remember

Its important to remember that any sleeping bag temperature ratings are based on estimates and many come (but not all) from an ISO standard in lab testing. Everyone is different and no rating will replace experience or good judgement when you are sleeping outdoors.