It's historically and physically proven that composite bows and crossbows lose velocity with getting wet. It's because the Horn arch and its composits dont grip that good on eachother anymore and the strength of the weapon it decreases..
1.) Why does the rain penalty for crossbows effect metallic crossbows (heavy crossbow; arbalest) too?
2.) Why does rain penalty not effect composite bows (Nomad-, Tatar-, Horn-, Rus Bow) ?