Can a Sleeping Bag Be Too Warm?


Figuring out a new sleeping bags temperature rating can be a confusing experience. Temperature ratings give you a quick way to compare sleeping bag warmth, but it’s not so cut and dry. With no upper temperature limit a lot of people wonder if a sleeping bag can be to too warm.

Yes a sleeping bag can be too warm, but you can always open up the zipper to air it out. I recommend purchasing a sleeping bag that’s 15 degrees lower than the temperatures you’re expecting and use a sleeping bag liner to increase your bags versatility.

Picking out a new sleeping bag and figuring out the temperature rating doesn’t have to be difficult. You can extend the useful temperature range of your sleeping bag by using the following suggestions.

Is Your Sleeping Bag Too Warm?

Waking up in your tent shivering is a miserable experience, but sweating isn’t fun either. Your sleeping bags temperature rating is the key factor when choosing a new bag.

There’s not much you can do about a sleeping bag that’s too warm. You can shed clothes and use the bags zipper to regulate the temperature, but that will only get you so far. Start off with the right bag and find alternate ways to add versatility to your bag.

If you have a reasonable idea of the coldest temperature you can expect, it’s easy to pick a bag. Pick out a bag that’s 15 degrees Fahrenheit Colder than your expected temperatures. It’s always easier to cool off a bag that’s too warm than heat up a bag that’s too cold.

I recommend purchasing a 40 Degree sleeping bag for 3-Season use (Spring, Summer, Fall). My Kelty Cosmic 40° Bag can be used from late March-November in Ohio. I need a liner and extra base layers on colder nights, but I’m perfectly comfortable.

It’s hard to beat a cheap Coleman Fleece Sleeping Bag Liner, which adds 12 degrees to your sleeping bag. A liner will extend the useful life of your bag and give you extra warmth in colder weather. My Sea to Summit Thermolite Reactor Extreme Liner was expensive, but it adds 25° to my bag.

A liner can be used without a sleeping bag in the summer and add warmth to your bag in the winter. The following section will give you more information about bag liners.

Unzip/Unbuckle Your Bag

Unless you pick a ridiculous mountaineering bag rated to -40° your sleeping bag shouldn’t be too warm. If you get too warm just unzip or unbuckle your bag to allow some cool air in.

If it gets really bad you can always stick an arm/leg out. You can even lay on top of the thing or use your bag as a quilt. That has always worked for me, but I’m a hard sleeper.

If you have a hard time regulating temperature you might need to go with a lighter bag. Use a sleeping bag liner and additional base layers to fine tune the temperature.

Men Sleep Warmer Than Women

Waking up covered in sweat seems to be a guy thing. Males tend to sleep hotter and deeper than women. So you’re more likely to overheat at night and continue sleeping until you’re a sweaty mess.

Men and Women’s sleeping bags actually have different temperature rating standards. Women require more insulation to stay warm so a women’s bag will be 15°-20° F warmer than a unisex bag with the same temperature rating.

Do You Wake Up Sweaty? (You could be carrying a lighter sleeping bag)

The trick is to cool small bits of your body as you heat up rather than waiting until you’re a sweaty mess. It’s hard to get back to the right temperature once you’re a sweaty pig. You end up cold out of the bag and too warm in it.

If you always wake up covered in sweat, than your bag is too warm. You could be carrying a lighter quilt or bag and shed a few pounds off your pack weight. Less weight on your back makes backpacking so much easier.

It can be really hard to find that goldilocks bag that can be used through spring, summer, and fall. Given that most nights start off warmer and slowly get colder it can be hard to rein in the perfect temperature.

A Liner Adds Versatility to Your Sleeping Bag

Clean is good! A bag liner protects your bag from dirt and body oils. A clean bag doesn’t require laundering swarmth to the bag, and can even be used on their own.

Do yourself a favor and pick up a sleeping bag liner if you don’t already have one. I use the Sea To Summit Thermolite Reactor Liner with all my bags.

It adds 25° F of warmth to my sleeping bag in cold weather and it’s warm enough to use on its own in the summer. With a quality liner, you should be able to use your 3-Season bag all winter long.

Pick A Sleeping Bag With a Full Zipper

Look for a sleeping bag that has a full length zipper if your worried about getting too warm. When you get too warm unzip the sides and use the bag to cover up like a quilt.

You can get away with a lot by switching up your liner and changing base layers.

A 32°-40° Bag Is Perfect For Most People

Instead of looking for the perfect sleeping bag pick the perfect temperature range. Unless you do a lot of winter camping a 32°-40° bag will be perfect for most people.

Once you figure out the temperature range continue to narrow your search by determining the maximum acceptable weight.

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