Not All Sleeping Bags Are Created Equal
Backpacking gives us a one-of-a-kind opportunity to shed everyday distractions and conveniences to enjoy being close to creation, even if only for a few days. Packing minimally and sleeping under the stars does not necessarily mean we have to give up a restful night's sleep. With the right preparation, we can sleep as snug as a bug in a rug while appreciating the silence and fresh air.
Have you ever slept in the summer desert with a winter sleeping bag made for 30F and below? Maybe you are still using that cheap sleeping bag with a broken zipper you've had for over ten years (which you probably bought at Walmart for a Spring Break trip). No need to be ashamed, we've all done it at one point.
My husband and I went on a backpacking trip at the end of May to Utah. Not only did we pack a winter sleeping bag for SUMMER, but it added a considerable amount of weight to our packs when traversing the desert. As you know, every ounce counts.
Sleeping bags are not a one-size-fits-all kind of deal. They require context: temperature, usage, weight, length, comfort, etc. My husband is 6'2" and tried to fit into my sleeping bag... he would have been more comfortable as a sardine in a can. He was being playful at home of course, but had he packed the wrong length bag, he would have been thoroughly uncomfortable.
I assure you, skimping on a quality sleeping bag fit for the occasion will simply result in a restless night's sleep. There are sleeping bags made for specific purposes (car camping, climbing, etc), but here I am going to address those used for backpacking. Much of the information learned here will also cross over to those purposes, but be sure to do your extra research for those instances.
Sleeping bags made for backpacking are often mummy shaped for a more snug and warmer fit. This means the shoulders are wide and gradually get narrow toward the feet. They typically come with an insulated hood for added warmth; I personally stuff my pillow in the hood to keep it from sliding around. Mummy shaped bags also cut down on the weight you will be carrying.
Sleeping bag size
Adult sleeping bags come in Regular or Long (and occasionally Short or X-Long). The best way to get the length you need is to look for the bags that list the "fits up to" height in the product specs. Regular often fits up to 72 in while Long may fit up to 78 in. You can also search for bags that differ depending on gender.
Generally speaking, sleeping bags can be narrowed down into 3 categories: summer, winter and 3-season. The chart below from REI is an average indicator of the temperatures associated with each type:
Summer Sleeping Bags
I know what it is like to sleep outside on a warm night with too thick a sleeping bag and it is less than ideal. That being said, it is a good idea to buy a bag that is rated to temperatures slightly lower than the lowest temperature you are expecting. For example, if you plan on sleeping on a summer night around 60-70F, have a bag that is rated around 50F+.
For the budget-minded backpacker, I recommend a synthetic or synthetic-down blend, which is quick-drying if you get wet. They are often more bulky than down, but I have actually found a great bag from REI that folds up really nicely into a sack and compresses well. I have never been so excited to see a sleeping bag in my life! It is dummy-proof for people like me who have trouble fitting a sleeping bag back into the little sack. See my recommendation at the bottom of this page!
Note: You may also consider using a liner for your summer bag if you are backpacking in an area that varies in temperature or altitude, like the mountains. This will easily give you a little added warmth.
3-Season Sleeping Bags
If you are primarily driving to day hike or kayak the lake and are coming back to the car, a 3-season sleeping bag will be a great option for you since weight will not be an issue as you are not packing it out. In the really cold months you can pack a blanket for extra warmth, and in warmer months simply strip down more and unzip the bag.
If you are backpacking, the 3-season sleeping bag is ideal for temperatures of 20 degrees F+ above, and are best used in spring and fall months. They are also beneficial in the summer if going to high altitudes when the temperature dips cooler in the evening.
Winter Sleeping Bags
In winter, I always recommend a down sleeping bag for added warmth. Down is an amazing insulator, and it is always better to be able to strip layers than to not come prepared. Winter bags are naturally larger in size than summer bags, but down will compress easier than synthetic, which will allow more space in your pack for more food and layers in winter weather.
However, consider where you are backpacking as it will lose its warmth if it gets wet (rivers, rain or snow). “Hydrophobic” down bags are treated to be water-resistant but are not waterproof. It is a good idea to invest in a waterproof bag to stuff the sleeping bag in when not in use.
If you are not backpacking in frigid temperatures, you could also use a 3-season sleeping bag and increase your warmth by adding layers. In cold weather, you should have already packed a down jacket, base layers, a beanie, etc., so this will not require packing any more gear than you already have with you. Wearing these items on chilly nights inside your sleeping bag will boost your warmth significantly.
Be sure to check out this article on How To Stay Warm On Cool Nights.
It is important to have a sleeping pad not only for comfort, but to act as an insulation layer between you and the ground, otherwise you will be absorbing the ground's temperature. Especially when backpacking, weight is crucial, so you will want a super-lightweight air pad like my recommendation below.
Check out this article by REI for a more in-depth look into various sleeping bags.