Once they are wet, matches are useless. As a precaution while camping or for any other use, waterproof matches are the way to go. No need to buy special matches though, Food Storage And Survival shows how to make your own with some nail polish.
Paint the match heads with fingernail polish. They need to be thoroughly covered. I like to go down the stick just a bit as well. You can also dip them into the bottle of fingernail polish, just blot them off on the edge of the jar on their way out -- you don't need them drowned in polish, just coated.
The blog notes that this can be a messy process, so it's best to roll out some newspapers and do your project on that. Once you're done coating the matches, let them dry completely with their edges hanging off, like in the photo above.