Here are some tips to staying warm at night while out in the wild.
- Sleep in a tent rather than an open shelter, lean-to, or “cowboy” camping. A tent can increase the temperature and provide more warmth.
- Choose your tent site wisely. Avoid camping near bodies of water and open spaces such as grass that invite condensation (which can turn to frost inside your tent on a cold night), dampness and a chillier night's sleep. Seek out areas out of wind and under what foliage there is (like pines or rhododendron for example).
- Make sure you have a good sleeping bag. Not all bags and their ratings are equal. Check the fill of the bag and the bag’s reviews with regards to how well it’s insulating properties matches the temperature rating it gives. Choose a brand name sleeping bag with a good track record. Don’t skimp on a good quality bag. Take along a sleeping liner also to better the sleeping bag’s rating, such a silk liner (which weighs little but can extend upwards of nine degrees to the sleeping bag rating – thus a 20 degree bag can work better in temps in the high teens)
- I have used a hand warmer in the past inside a sleeping bag to help, but they must be used with care as they can get quite hot and could cause discomfort and sometimes even burns if used improperly. Others suggest a platypus bottle filled with hot water to warm a sleeping bag, but I hesitate having liquid in a bag on the chance something could leak - then you'd be in trouble.
- Use a good sleeping pad. The R-value of the pad is important. Taken from the REI web site – “Insulation is measured according to its capacity to resist (that's the "R") heat flow. The higher a pad's R-value, the better you can expect it to insulate you from cold surfaces.”
- Be sure you eat a warm snack before bed and keep up your fluid intake. This adds more fuel to the fire in your body, so to speak, and will keep you warmer.
- Wear a good insulating layer to bed such as a merino wool baselayer (but don’t overdress!) and wear a hat to bed.
- Also, if you carry electronics and battery-operated devices, be sure the batteries and electronics “go to bed” with you. They will stay charged a lot longer if kept warm. I have been known also to sleep with my headlamp.