It's that time of the year for me. Time to pull out all the gear while my wife is traveling for work and lay it out all over the house so I can put the heavier clothing and sleeping bags in it. This process requires a great deal of self control for me, mainly because I'm itching to purchase a high dollar lightweight down bag for my recreational kit and put my current 20 degree Browning bag into the Minuteman Cache.
Winter brings with it many issues that can compromise your gear and your body. You'll need to have solid and warm footwear as well as warm, layered clothing to suit many temperatures. Rain becomes a critical issue as well. Even the warmest clothing can sap your body temp when soaked with cold rain and wet snow. Your gear should also leave room for body armor. Without a doubt, I've seen body armor left behind during training due to the inability to fit clothing under or over it. This is not an acceptable practice. Test your kit every chance you get. You may look funny hiking with your armor and pack, but don't worry, embarrassment or funny looks won't kill you, it's the bullets that you must look out for. In recent months I've witnessed several people out jogging and rucking with a PC and plates. None of it was military issue and only one was police issue. The local Crossfit gym that I used to belong to had armor days, but not that often.
Water filters are prone to freeze and once frozen with water in the system, can allow bacteria to pass through the membrane due to the swelled pores from frozen water. Imagine that when you actually need to use the gear, your water filter doesn't work. One way to counter this is to purchase new units for unused kit and replace a worn out filter with a new one from a Cache or bag you don't use regularly. It's similar to setting up your kit for a car. Once used, your filter should be on your person to keep it from freezing in cold temperatures and in your sleeping bag overnight, along with some water to keep it from freezing. A little hack I learned from a friend is to heat up some water on a cold night before bed and climb into bead with some nice warm water bottles. Being able to hydrate a meal with water that's not frozen is far more expedient than thawing ice with your stove before eating. It would also use less fuel and not boil off as much water as otherwise. He also taught me to heat up rocks and put them in your boots to help dry them out at night in your tent or sleeping bag. Worked like a champ the one time I tried it.
My trailer equipment is also getting the winter treatment. I'm putting all the military sleep systems back together and making sure the fuel situation is in good order by checking to see how the diesel looks and smells. My generator is also getting the fuel cycled out of it. The one time I needed it 2 years ago, the fuel lines were frozen solid. Never again!
I'm adding a tent or means of making a tent to each kit as well as upgrading the tarps I rely on in a pinch. I've learned that the light to medium use tarps don't hold up well to a good NorEaster in sub zero temperatures. Another little trick I've learned from some survivalist was to purchase some bubble wrap that's made of tinfoil that's backed on both sides with tinfoil for an extra layer of lightweight insulation when you desperately need it. It can be rolled into your normal bedroll or use it to line your pack, but it's a very cheap and easy hack to extend the ability of your sleeping bag or sleeping mat. Some people cut it to fit inside their sleeping bag and put it between the bag and a liner of some type for additional insulation when on frozen ground or in a hammock. It's used quite a bit for pot cozys and such. Very economical solution for many issues where you need a thin layer of insulation. I will put some in the knee pad slots in my pants when it's cold out to protect my knees when kneeling on cold or wet ground. Tape the edges though, they can get loud when moving. Gorilla tape works better than the silver tape you would use for cozys and such.
Remember to relube your firearms with cold friendly lube such as EWL or a commensurate product of similar consistency. Adding a plastic birdcage cover will also keep your bore clear in heavy snow or boggy conditions. Your glove choice will need to be firearm friendly as well. I wear liners and overgloves with an extra right glove with the fingers cut down to the second knuckle. The liner keeps the wind off and the thicker glove keeps the hand warm. Military mitts with removable finger covers work well too.
Winter also means your food intake will increase if you are out in the elements at all. Pack accordingly. I tend to drop some ammo and add some extra Knorr sides into the pack for extra calories. Soft water bottles or bags are easier to keep inside your coat than steel bottles. Grab a couple for 10 bucks, they weight nothing when empty and are a great winter addition to your gear. I like Platypus brand for expense/durability trade off.
In my Caches, I put a white sheet from goodwill in the bin for easy snow camo in a pinch. Cut a head hole and wear it like a poncho "Rambo style" for hillbilly snow camo. Winter time is a prime time for thermal imaging equipment to function at it's best. The disparity in temperatures between the environment and your person shows as a glaring contrast by anyone with an entry level thermal scope.