You bought an expensive 0°F sleeping bag. You wore wool socks. Yet, you woke up at 3 AM shivering uncontrollably.
The problem isn't your bag. The problem is the ground.
The ground sucks heat away from your body 3x faster than the air. To stop this, you need to understand one critical number: The R-Value.
What is R-Value?
R-Value measures a sleeping pad's ability to Resist heat flow. The higher the number, the warmer you will be.
The Cheat Sheet:
- R-Value 1 - 2 (Summer Only): Good for warm nights (50°F+). These are usually cheap air pads.
- R-Value 3 - 4 (3-Season): The standard for Spring and Fall. Handles cool ground well.
- R-Value 5+ (Winter): Essential for snow and freezing ground. Usually insulated with down or synthetic fibers.
The Beginner Mistake
Many beginners buy a cheap yoga mat or a generic air mattress with an R-Value of 1.0, then wonder why they are freezing in October.
Pro Tip: R-Values are additive! You can stack a foam pad (R-2) under an air pad (R-3) to get a winter setup (R-5).
Related: Don't let the cold ruin your trip. Check out 7 Beginner Mistakes to Avoid.