Temperature Ratings on Mummy Bags: What Do They Mean?

Sleeping bags today offer a lot of choices with various materials, weights, shapes, and temperature ratings. Unless you are an experienced backpacker, it may be a bit intimidating to evaluate all your options and get the right sleeping bag for you. When backpacking or camping in high altitude or even slightly chilly nighttime weather, a mummy bag will keep you warmer. 

EN Temperature Ratings for Mummy Sleeping Bags

The temperature rating on a mummy bag is the main factor which will indicate to you the warmth the mummy bag will provide. Most sleeping bag manufacturers use the EN temperature rating system, which indicates the lowest temp that you can expect your sleeping bag to keep the average camper warm at night. 

For example, if your mummy bag says it is rated for 30°, you should expect the average person would be comfortable if the temp got as low as 30°F, but they may not be warm at a temperature less than that. A good practice is to choose a bag with a rating of 25° less than what you expect the coldest weather to be. 

In spite of the direction these ratings can provide, the United States currently has no standard to measure these ratings and many variables can affect how warm a person will feel that just cannot be replicated in a testing lab. For example, a person with a high metabolism may not feel as chilled as someone else and most women sleep colder than men. Other factors include whether you are using a sleeping pad (highly recommended), the clothing you wear and the material of your mummy bag. 

Mummy Sleeping Bag Temp Ratings for Different Seasons

You should always keep your regional climate in mind as the temperatures across the U.S. vary widely during the seasons. This is a rough seasonal guide to mummy bag temp ratings for the average person in average seasonal temps, all listed in °F:

• Indoors: any bag with 45° and up will do

• Summertime tent camping outdoors: 30° or greater

• Spring and Fall tent camping outdoors: 20° to 30°

• Winter camping outdoors: 0° to 20°

• Deep winter outdoor expeditions: -40° to 20°

It is important to evaluate each outing and compare to the seasonal temps and any expected variations such as an exceptionally cold winter or warm summer. For additional questions on choosing the right mummy bag for your adventure, contact the outdoor experts at Cascade Mountain Tech. Here you will find a large selection of high quality mummy sleeping bags, rotomolded coolers that keep your ice for several days with bear proof ratings, and a wide selection of hiking trekking poles to suit any hiker of any size. Our camping chairs are the best in quality with a wide selection for any setting.

Cascade Mountain Tech believes in providing affordable adventure to anyone, with a wide selection of hiking and camping gear. We offer expert tips from experienced outdoor enthusiasts and high quality gear for a successful camping trip. Contact us with any questions and to learn more about how to choose the right mummy sleeping bag.