Winter camping requires exprience to detemine what gear you need. When I first started winter camping, I would take my entire gear closet. Now I take the minimum amount needed. However, there is still extra weight and what seems to add the most weight is the sleep system. The sleep system is the most important piece of gear for your winter camp. We found that not having your sleep system well put together will make for a miserable night. It's important to, before the winter comes, find out what exactly you need to keep warm. I found that the particular sleep system I used works best if I put my coat inside and around my feet. I have a problem with my feet getting cold and that was one thing I had to learn to compensate for. While in our hammocks, my camping partner had troubles keeping his butt warm and had to find how to compensate for that. So before you go on a full blown winter camp, you should find what works best for you to keep warm. If you camp all year long, late fall is a good time to get out and discover what you need to improve on.
Since there was only two of us camping, we narrowed it down to two stoves. Our first trip this winter, we started with three. With multiple people in your party, it's much easier to have each person cooking a different part of the meal. In our case, I was browning the meat as he cooked the noodles, then mixed the two into both pots. After dinner, we used one stove to heat water for hot chocolate while the other was used to heat water for our Nalgene bottles.
Our first camping trip this winter, we had a hard time keeping a fire going. In the sub-zero weather, or even around zero, the fire seems to go out quicker. With that being said, it's important to have enough fire wood for the night. I cut enough wood to overfill my pulk and that seemed to be enough for one night. If the fire goes out, it can be difficult to restart. I found that the fires started easier by using LOTS of little twigs and a fire starter. For a fire starter, we used cotton balls soaked in petroleum jelly. This works exceptionally well. As you collect wood, be aware that if it is frozen and has even minimal snow on it, you will have a hard time starting it. I found that the best wood to use is branches cut from dead trees. They seemed drier and started easier. You can also precut and store wood, then haul it in your pulk.
Fire is an essential tool for keeping warm in the winter, though proper dressing will provide adequate warmth. However, it's difficult to keep a fire going overnight without monitoring it. To keep warm in the sleeping bag, it helps to stuff your clothes in with you. This not only helps to provide insulation, but keeps your clothes warm for morning. We also boiled water over the stove and filled our Nalgene bottles. By putting the bottles in your sleeping bag about an hour before going to bed, you will have a very warm sleeping bag. We also boiled the water right before bed to keep them warm. We crawled in our sleeping bags around 10:00 and my Nalgene bottles stayed warm until about 5:00 AM. I used two Nalgene bottles, but I think this winter, I will use three or four. The one downside to this method is when the bottles cool down, they can actually make you colder than you would be otherwise.
In addition to the bottles, I found that placing a large space blanket between the hammock and underquilt helped to keep the hammock warm. I had enough blanket to also pull it over me to trap the heat. The downside is that space blankets are not breathable and can accumulate condensation. Condensation can be a problem with hammock camping. I found that in the morning, my sleeping bag and hammock was covered in frost. One way to combat this is to make a frost shield. This can be done by taking an old t-shirt and cut out the neck hole and a large square from the front. The neck hole can be placed around the neck and the end of the square can be tied to the ridgeline. This way, any condensation will accumulate on this and not the sleeping bag.
This year, I also started bivy camping. Bivy camping is an experience if you have never tried it. I will post on bivy camping later, but what I do want to convey is that bivies trap heat really well. I did an open bivy camp this winter and found the bivy adds significant warmth.
When you camp in the cold, remember that your body burns more calories to keep warm. Therefore, it's important to eat at least one good meal a day. Eat something with high calories and protein. Throughout the day, it's a good idea to also snack on high calorie and protein snacks such as nuts or ClifBars.
Lastly, I want to cover hauling gear. I started out with my usual Teton pack. I pack my bag the same every time and found it convenient to pack it the same as I do in the summer, then pack all of my winter specific gear (sleeping bag, extra fuel, wood, etc.) in the pulk. It didn't take long for me to realize this gets very heavy. I eventually refined my gear list to just the essentials and used only the pulk. A pulk is so much easier to haul gear than a pack in the winter. In all reality, I don't take as much for winter as I do summer.
Even though these tips are intended more for winter, I decided to post them now and primarily for two reasons. One: because they are still fresh in my mind. Two: because they can also be used in summer months. Some summer months can get cold at night and for those living in colder regions, these tips will still apply. Remember that the best way to improve on your camping skills and learn these little tricks is to get out there and camp often.