"A 15- or 20-degree sleeping bag offers the greatest versatility for the widest range of conditions. It's the temperature range I use on the majority of my excursions—which is why I would consider spending a little extra money to get the lightest, most compact version I could find."
—Matt Heid, Appalachian Mountain Club's “Equipped” blog, 7.22.10
Questions Addressed in This Debate
What weight of sleeping bag should I carry into the mountains? A warmer sleeping bag to handle at least the coldest expected conditions or a lighter bag supplemented with all my extra clothes if it turns colder than expected? To what extent should I sacrifice comfort for a lighter weight sleeping bag? Does an ultralight backpacker have to sacrifice sleeping comfort? Should I view all of my clothes (jackets, hats, gloves, wind shells and even storm gear) as part of my sleeping system?
Competing Options for This Debate
What weight of sleeping bag/quilt should I carry into the wilderness (assuming I have a choice of bags to buy or carry):
— a bag/quilt that will usually handle the expected conditions?
— a bag/quilt that will handle at least one level colder temperatures than what are expected?
— the warmest bag/quilt I can afford that will easily fit into my pack?
— a lightweight or an ultralight bag/quilt that will often need to be supplemented with extra clothes for warmth?
Statement of Competing Positions by Two Experts
For some, the extra clothes approach is not a real option. Here is Chris Townsend, a highly experienced backpacker and author, expounding this view in his book The Backpacker’s Handbook, 3rd edition, page 220:
Some people just pile on extra clothes at night, but I’ve never met anyone who does this by choice (a forced bivouac when you aren’t carrying a sleeping bag is another matter), and it sounds both uncomfortable and inefficient.
Another highly experienced backpacker and author, expounds the opposite position:
. . . it makes no sense to carry an excessively large, bulky and heavy bag throughout the day, and then to sleep alongside a pile of perfectly adequate, insulating clothing at night. In my quest for a lighter packweight, I have come to believe that the opposite approach makes far more sense: that is, to carry a thinner, lighter-weight quilt or bag, and to wear those clothes when the nights are chilly. This approach saves money, packweight and bulk, without compromising nighttime comfort in the least. And as a bonus, I find it quite pleasant to rise on the coldest of mornings already dressed in warm clothes.
—Ray Jardine, Beyond Backpacking, page 100
Two experts and two opposing positions. To get a better handle on this topic, let’s analyze the two issues raised (comfort and efficiency) to see if we can take this debate to a higher level.
Analysis of Sleeping Efficiency Issue
The efficiency issue can be dealt with quickly and easily: carrying unnecessary weight with a heavier sleeping bag (especially if it is a synthetic bag to cover all of the conditions that might occur) and a larger pack to carry it in is not efficient. The wear-your-extra-clothes-to-bed person wins the efficiency argument easily. However, it must be granted that when “base” camping (i.e., humping in many comforts and then day hiking out from there) the concern for efficiency is usually irrelevant.
Analysis of Sleeping Comfort Issue
The comfort issue is much more interesting and somewhat complicated. Let’s start our analysis with a clear statement of the specific issue:
Should I carry a heavier sleeping bag that will guarantee warm sleeping in the coldest conditions expected without supplementation, or expect to wear almost all of my extra clothing to bed in weather colder than expected to supplement a lightweight bag?
To make headway analyzing this issue, four clarifications are in order. The first is that sleeping in your extra clothes (the primary issue of this section) is not the same as sleeping in your dirty and sweaty trail clothes. Maybe this is part of what Townsend was objecting to. Of course, if you totally underestimate the temperatures, sleeping in ALL your clothes might be a necessity, at least for a day or two. A second clarification is to assume that the sleeping bag has enough space for wearing most or all of one’s extra clothes. Maybe Townsend is claiming that wearing extra clothes to bed is uncomfortable because his bag was too small to wear extra clothes comfortably. If the bag were too small, it would be more comfortable to drape the extra clothes over the top of the bag. The third clarification is making a distinction between comfort and convenience. It is obviously more convenient to unzip and zip up a sleeping bag to maintain comfortable temperatures than it is to add and subtract clothing. Maybe this is what Townsend meant by inefficiency. But convenience and comfortable sleeping are two separate issues.
Finally, let’s assume we are not talking about wearing damp trail clothes to bed for the purpose of drying them out. This is usually not comfortable. For additional perspectives on this interesting side issue see “Cold and Wet Weather Hiking.”
Assuming the four clarifications and assumptions detailed above are acceptable, what are the main comfort-related arguments? First, consider the comfort of sleeping attire. Sleeping in one's close-fitting long underwear and insulated clothing (the usual arrangement for the lightweight packer) isn't as comfortable as sleeping in loose-fitting trail pajamas, but if one is tired from a full day on the trail, does it make any practical difference? Besides, most long underwear made for outdoor recreation these days is quite comfortable. Not only does it transport sweat moisture away from the skin, but it also feels quite soft next to the skin.
A second comfort-related argument could be made that extra clothing can get twisted during the night and feel tight. But the reality is that the main piece of extra clothing used to sleep in is an insulated jacket or parka that will not get twisted if worn normally (i.e., zipped up with arms in the sleeves). If the extra clothing item is a hooded parka, the hood will move with the sleeper.
Two additional comfort-related arguments can be made in favor of the wear-extra-clothes-to-bed position: (1) the point Jardine made above about arising already warmly dressed in the middle of the night to pee or upon getting up for good on a cold morning; (2) the additional comfort on the trail of carrying a lighter sleeping bag in a smaller pack. Granted, the weight these last two arguments have would depend a lot on the specific conditions at the time (e.g., how cold the nighttime temperatures are and the number of miles traveled), but they are needed to provide a more complete perspective on the issue of comfort.
An argument favoring the “anti-extra-clothes-to-bed” person is that they would have the advantage in being able to wear their extra clothes to bed if a totally unexpected low nighttime temperature actually occurred. In this scenario, the lightweight bag person would not only wear ALL of their clothes (including wind and rain shells), but also resort to many of the enhancements related in the article A Good Night’s Sleep In The Backcountry.
A final comfort-related argument focuses on the essence of backcountry sleeping comfort. Consider that there are probably only two real comfort criteria: (1) having enough padding underneath to avoid feeling the hard ground; (2) maintaining proper body temperature (i.e., warm = comfort; chilled = discomfort; too warm = discomfort). The first criterion (sleeping pads and selection of camp sites) raises issues not dealt with in this article. The second criterion for backcountry comfort (maintaining proper body temperature) obviously isn’t biased about the cause of the proper body temperature. The cause (e.g., hot water bottle, extra warm sleeping bag with a full zipper opening, wearing one's extra clothes to bed, eating high-calorie food before bed, maintaining high metabolism levels) shouldn’t make much difference as long as one is sleeping warmly.
The above in-depth debate and analysis should firmly establish whether you are or are not a “wear all your extra clothes to bed” type person. However, you might want to deal with additional variables related to this debate. For example, how important are economy and efficiency and ease of use in the backcountry? How important are comfort and convenience in backcountry travel? How important is packing light? For an in-depth analysis of the latter two issues, consider reviewing the following: The Challenge of the Lightweight Packing Movement and The Importance of Maximizing Comfort and Minimizing Discomfort in the Backcountry