Temperature Rating
What is a Temperature Rating?
A temperature rating is a standardized measurement that indicates the lowest temperature at which a sleeping bag or outdoor gear item will keep a user warm and comfortable. For sleeping bags, it typically includes comfort rating (temperature at which an average woman sleeps comfortably), limit rating (temperature at which an average man sleeps comfortably), and extreme rating (survival temperature with risk of hypothermia). This rating system helps campers and backpackers select appropriate gear for expected weather conditions and ensures safety during overnight outdoor adventures.
Related Terms
Comfort Rating
A Comfort Rating is a temperature specification for sleeping bags and sleeping pads that indicates the lowest temperature at which an average user can sleep comfortably without feeling cold. This rating is typically higher (warmer) than the survival or limit rating, representing the temperature where most people will have a comfortable night's sleep. For sleeping bags, it's usually tested with a standard sleeper wearing base layers, while sleeping pad comfort ratings indicate the temperature range where the pad provides adequate insulation from the ground.
Lower Limit
A lower limit is the coldest temperature rating at which a sleeping bag is designed to keep an average woman comfortable during sleep. This rating is part of the EN (European Norm) or ISO temperature rating system used to standardize sleeping bag performance across manufacturers. The lower limit typically runs about 10-15°F warmer than the extreme limit rating, providing campers with a realistic expectation of the bag's warmth capabilities for planned camping conditions.
EN 13537
EN 13537 is the European standard for testing and rating sleeping bags, providing standardized temperature ratings that help campers and backpackers choose appropriate sleep systems. The standard defines four temperature ratings: Comfort (for women), Lower Limit (for men), Extreme (survival threshold), and Upper Limit (maximum comfortable temperature). These ratings are based on laboratory testing with thermal manikins and provide reliable, comparable temperature guidelines across different sleeping bag brands and models.