Choosing a Sleeping Bag Temperature Rating

It can be hard to choose the sleeping bag temperature that will be best for you. The most important function of a sleeping bag is keep to you warm when it’s cold out, but you also don’t want to sweat all night when it’s warm out. Finding the right balance can be difficult enough that a lot of serious outdoors-folk have multiple bags. However, the normal, a budget-conscious recreationist like myself can’t always afford multiple, quality sleeping bags. So how can you choose a sleeping bag that will keep you comfortable in multiple seasons?

If you’re looking for one sleeping bag to use year-round, a 10°F to 20 °F sleeping bag is probably the best option. During the winter months, you can add a liner to increase the warmth. In warmer climates, you may want to bump the temperature up by 10 °F, or so. If you do mostly summer-time trips, a 30 °F sleeping bag should keep you comfortable.

When you select a sleeping bag, make sure it is rated using EN or ISO testing standards. If your sleeping bag is not tested by these standards there is a good chance it won’t be as warm as advertised. I’ve made a guide about the EN and ISO sleeping bag temperature ratings, so you know what the ratings mean and how to determine the protocols used to test the bag.

When and Where Do You Use a Sleeping Bag Most?

To decide what temperature sleeping bag you should get you first need to know when you will be using the sleeping bag. If most of your camping or backpacking is in the desert during summer you don’t need a 0 °F bag. On the other hand, if you spend a lot of time doing backcountry ski trips in the winter, you don’t want to get a 30 °F bag.

If you mostly use a sleeping bag while car camping the temperature rating won’t be as important because you can easily bring extra blankets and clothes to use if you get cold. However, if you’re using the sleeping bag in the backcountry you’ll need to trust it’s warmth to keep you safe if an unexpected cold front rolls in, or if you get wet and need to warm up to prevent hypothermia.

It’s also important to consider the terrain you’ll be sleeping in. Temperatures in the mountains can change dramatically as storms quickly roll in. That’s why I usually take a sleeping bag that is warmer than I think I’ll need when in the mountains because I want to be prepared if I encounter colder temperatures.

Desert temperatures can drop a lot at night, but the weather patterns are generally more stable and predictable.

Think about where you’re going to spend the most time sleeping outside, then determine what the weather is like in those locations. Once you’ve decided on those things, picking a temperature rating becomes much easier. Especially if you’re only camping during a single season.

The maps below can help you determine what the seasonal low temperatures will be like for the areas you visit most. Recent maps can be found at


Choosing the Temperature Rating for a Single Season Sleeping Bag

For single-season use, it’s pretty simple to choose a sleeping bag temperature rating. Look up the average low temperatures for the locations you usually visit during the season you’re there. Then find a sleeping bag with a temperature rating slightly lower than that average low temperature.

For a summer sleeping bag, a temperature rating between 20 °F and 40 °F should be adequate, depending on your location. In winter you’ll probably want a bag rated between -10 °F and 10 °F. For spring and summer, a 20 °F to 30 °F bag should do the trick. When I’m uncertain I usually err on the side of more warmth.

Of course, adjust these recommendations for the specific areas you visit.

Choosing a Temperature for a Multi-Season Sleeping Bag

Choosing a sleeping bag temperature is more complicated when you want to use it across multiple seasons. In this case, you need to balance staying warm enough when it’s cold against being uncomfortably warm when it’s not. It’s always best to lean toward a warmer bag because you can always unzip it or sleep on top of it, but you can’t add extra warmth when it gets really cold.

If you spend time in the mountains from late spring through early fall I would recommend a 20 °F temperature rating. You can get a 20 °F bag that isn’t too heavy or expensive but will still perform in a lot of situations. If you’re in a warmer or colder climate you may want to adjust by 10 °F or so in either direction.

For those that regularly sleep outside in both warm summer temperatures and cold winter temperatures, it’s probably best to get two sleeping bags. Get one with a 20 °F-30 °F rating (again, depending on location) to use in the warmer months. Then get another sleeping bag with a -10 °F to 0 °F rating for the cold months.

Temperature Rating for a Backpacking Sleeping Bag

I’ve already mentioned that I take a warmer sleeping bag than I think I’ll need when I go into the mountains. This is especially true when I’m backpacking.

In the backcountry you only have the supplies you carry with you. If an unexpected cold front comes in when you’re a 2-day hike from resources you have to make do with what you have.

A sleeping bag is arguably the most important piece of gear you carry on a backpacking trip. If things go south and you’re in a situation where hypothermia is a concern your sleeping bag is the best piece of gear you have to keep you warm. If you brought a 40 °F bag on a trip where a cold front brings in 20 °F overnight lows you’re going to have to work to find ways to stay warm.

After you’ve done a few backcountry trips you’ll get a feel for the temperatures and weather patterns in the areas you visit. You’ll also learn things you like and don’t like about the gear you have, and that will help you make informed decisions.

If you’re just starting out and don’t have a feel for the temperature rating you need I would recommend a 20 °F bag for most backcountry activities from early to late summer. The 20 °F temperature rating should keep you warm throughout the summer months while keeping the size and weight of the sleeping bag down.

Make a Sleeping Bag Warmer

Eventually, most of us encounter a situation where we have a sleeping bag that just isn’t warm enough. It can happen because the weather changed without warning, the temperature rating on a bag wasn’t accurate (see this guide to help prevent that), you didn’t have the budget to buy a new bag for a late-season trip, or a number of other reasons. If you end up in this situation there some simple things you can do to increase the warmth of the bag you have.

Wear Extra Clothes

You’ll be amazed at how much wearing extra clothes, especially a hat and socks, will warm you up at night. I’ve spent a lot of cold nights in a bag that wasn’t warm enough (because I was a cheap college student) and stayed warm all night by layering up with clothes inside my bag.

Use a Sleeping Bag Liner

Sleeping bag liners that slide inside your bag can also increase its warmth. These liners are usually quite affordable and make it easy for your bag to function well in multiple temperatures.

Double Up

You can take the liner idea farther by using two sleeping bags, sliding one inside the other. This is a good option if you’re car camping and have two sleeping bags for warmer weather. I’ve done this several times with two 30 ° F bags when temperatures were below 20 °F and have stayed toasty warm.


Choosing the proper temperature rating for your sleeping bag will help you be safe and comfortable whether you’re sleeping 30 miles from the trailhead or right next to your car. The budget-conscious outdoors-person can probably make one sleeping bag work for year-round use by using a liner or extra clothes to stay warm in the winter. By considering your needs and range of use before purchasing a sleeping bag you can make sure the temperature rating you select will support the majority of your outdoor pursuits.

Konrad Hafen

Konrad is a natural resource scientist who spends much of his free time hunting, fishing, hiking and backpacking on America's public lands.

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