Choosing the appropriate sleeping bag rating for winter is a challenging situation to be in. If you’re stuck in deciding the right sleeping bag rating for winter or mountaineering, I am going to help you choose the one that best fits your winter camping needs.
Unless you are into mountaineering, a sleeping bag rated at -10°F/-23°C is recommended for winter camping. For camping at higher elevations go for at least -20°F/-29°C. Whereas for extreme expeditions, choose a sleeping bag rating of -49°F/-45°C or below.
This article is not about understanding how sleeping bags are rated in the lab. I assume that you already understand the sleeping bag ratings.
However, to give you some perspective, here is a brief overview of how sleeping bags are rated in the test labs by EN and ISO rating systems.
Sleeping Bag Ratings Brief Overview
Sleeping bag manufacturers send their sleeping bags to an independent test lab. Most of them have adopted EN (European Norm) and ISO testing methods.
Adopting the same testing method by all the sleeping bag manufacturers in the world is helpful for ensuring consistency and accuracy in the industry.
For example, a sleeping bag at Feathered Friends rated at -20°F should keep you as warm as the same rating sleeping bag taken from Big Agnes.
Popular brands like Western Mountaineering, Big Agnes, and Feathered Friends set their own temperature ratings. Their method of testing is highly accurate as well.
Sleeping bags are rated based on the assumption that you’re sleeping on a closed-cell foam sleeping pad and wearing long underwear top and bottom. Also, you’re sleeping in a tent.
No matter where you are planning to set up your winter camp, a quality sleeping pad is critically important besides a sleeping bag.
Not only does it provide a soft surface to sleep on but also prevents your body heat from dissipating to the ground.
I have written an article on Is a Sleeping Pad Necessary For Camping? Check out that as well.
What Temperature Should a Winter Sleeping Bag Be?
A good rule of thumb is to subtract 10 degrees from the coldest conditions you anticipate. Let’s say, if the expected coldest temperature of the region where you intend to do winter camping is -25°F, you should go for a sleeping bag rated at -35°F.
Sleeping bag ratings are just estimates. For safety, you should give a 10-degree buffer when purchasing the winter sleeping bag.
When you are planning winter camping, there are three different situations. Either you will be winter camping at lower elevations or higher elevations/mountains. The last situation is going for extreme expeditions.
Depending on your situation, choose a sleeping bag rating that can keep you warm no matter what the temperature of the region is.
For winter camping at lower elevations (plains and deserts), I would recommend a sleeping bag rated at 0°F/-18°C.
Whereas, for winter camping in the mountains go for a sleeping bag rating of -22°F/-30°C.
If you’re into mountaineering, choose a sleeping bag rated at -60°F/-51°C or below.
Keep in mind that the lower-rated sleeping bags are heavier, bulkier, and more expensive than the higher-rated sleeping bags. Therefore expedition bags are more expensive.
If you are on a budget and also want to cut down on weight you can go for a 3 season sleeping bag along with a sleeping bag liner.
Wearing a base layer, wool socks, and a down jacket will increase the warmth inside the sleeping bag.
How Warm Should a Sleeping Bag Be For Winter Camping?
Women tend to sleep colder than men. When you go to purchase a sleeping bag, there are two separate ratings listed on the sleeping bag: Comfort and Lower Limit.
The comfort limit is the lowest air temperature at which an average female or cold sleeper would sleep comfortably.
On the other hand, the lower limit is the lowest temperature at which a male or warm sleeper would sleep comfortably through the night.
Regardless of your gender, go for something that can keep you warm in the weather conditions of the region where you plan to do winter camping.
Your sleeping bag should be 10 degrees warmer than the coldest temperature anticipated in the region where you do winter camping.
To make things easier for you, If you are planning to do winter camping in the Alaskan region where the lowest expected temperature would be -22°F then go for a sleeping bag rated at -32°F.
If you get warm you can shed some clothes, unzip the sleeping bag, or bring your leg outside. However, if you get cold there is nothing more you can do.
Therefore, you should give a buffer to be on the safe side. After you are done with the ratings the next thing is to go to the store and purchase the sleeping bag.
If you’re a male look for the Lower limit and if you are a female see the comfort rating on the sleeping bag.
Apart from the sleeping bag temperature rating, factors such as sleeping bag shape, size, brand, the food you eat, gender, and layering also impact the warmth.
What Is The Coldest-Rated Sleeping Bag?
Expedition bags are the coldest-rated sleeping bags. They can go all the way -60°F/-51°C and below. These are extreme expedition sleeping bags designed for mountaineering.
Everest, K2, South Pole, 8000m peaks, and places like Alaska demand such expedition bags.
Winter Sleeping Bag Rating
Picking an appropriate temperature-rating sleeping bag for your adventures should not be that hard.
The bottom line is that if you’re stuck in choosing the sleeping bag rating for winter go for a bag rated at least -22°F/-30°C.