Fire is a very useful source of emergency light when you are in the wild. Apart from allowing you to see what is happening around, it also aids in scaring away animals and other harmful creatures in the wild. It is however impossible to start a fire when it is raining.
This waterproof fire starter tinder can however help you get fire when there was light. Also it could keep you warm and protect you from the cold that comes with the rain.
You can make your own tinder- collect dryer lint. Put it in zip lock bags. Shred newspapers, and put them in zip lock bags as well.