Why is my sleeping-bag soaked every morning??

[PatmanTN]

Fallesafe,

This is an interesting issue and I'll add this for what it's worth: I have a WM microfiber Lynx (rated to -10F) as my deep winter bag and I have the exact same issue no matter what shelter I use (typically double wall). The top of that bag is almost always wet in the morning. I can't explain it technically but I think its something to do with high-loft bags and that shell materiel. I always bring along a little towel to wipe it down in the mornings (my bag not the tent).

[Coffee]

Over almost a couple hundred nights in my Hexamid Twin over many years, condensation is just a fact of life in some settings, but very much avoidable in other settings. Particularly out west, I am usually able to avoid the worse of the condensation problem by good campsite selection and ventilation, which is helped by the dry air with very low humidity. In fact, the only times I have suffered from condensation in the West is when I have camped in or near meadows or very close to bodies of water. Camping under a tree canopy elevated from lakes or streams usually avoids the problem. Ventilation is also critical. Closing the vestibule is recipe for condensation.

On the AT, with the higher humidity of the eastern United States creates many more challenges. For the most part, I avoid backpacking in the east during the hottest and most humid summer months. By September in the mid-Atlantic, conditions are much less humid usually and less prone to condensation issues.

I own but have yet to use a zPacks Altaplex (it was intended for a thru hike out west that I had to cancel). In theory, the Altaplex should have less condensation issues because it looks like it is more open for air circulation. I may be selling the Altaplex, however, since I am definitely not going to be able to thru hike for a while and my Hexamid Twin is still OK for the few overnights I might be able to fit in for the foreseeable future.

Single wall vs double wall is obviously a weight issue. The Copper Spur UL 2, super popular tent, is almost three times the weight of a minimalist single wall shelter.

[MapleHiker]

I've gleaned much information from you over the years Tipi. You should write a book about your travels and all the emperical knoweldge you've acquired in doing so.

[wornoutboots]

I agree with opening up your tent in colder (all conditions) I sleep in a Copper Spur 2 & always have 1 door rolled open. I just returned from the Big South Fork where I slept 100 feet from the River in low 40's and woke to a dry tent, sure it was a little colder but that's why you bring a warm bag and an adequate pad.

[TwoSpirits]

Agreed. I try to always sleep with at least one vestibule of my tent as open as [precipitation] conditions allow. I have still had some frost build up inside, but definitely manageable.

When using my full-fabric inner tent in very cold and blowing snow forces me to keep the vestibule closed, I try to create a "draft" inside by cracking the door low on one side and high on the opposite side...the thinking being that the cold air will enter on the low side and push the warmer, moist air out the high side. I do still get frost, but I think it helps a little. ?

My biggest challenge moisture in/on my sleeping bag is dealing with how it is always wet (and icky!) right near my face, due to my warm breath on it all night. I avoid burying my head & face inside, and wear a buff over my mouth and nose, but still deal with that.

[George]

best way to avoid condensation: stop breathing

[Time Zone]

On the AT, with the higher humidity of the eastern United States creates many more challenges. For the most part, I avoid backpacking in the east during the hottest and most humid summer months. By September in the mid-Atlantic, conditions are much less humid usually and less prone to condensation issues.

Relative humidity can still soar overnight, even peg the needle, in the cooler months of the east. Part of that is the definition - cooler air holds less moisture, so it's easier to get higher RH readings. But still, even with a cool dry day, RH can spike overnight. It's almost always something to consider.

Synthetic bags won't collapse loft with moisture, but they can still get damp from condensation, and therefore should also be aired out to dry in the daytime.