Moths don't do well in water. When they get wet, the fuzz on their bodies and the tiny translucent scales that cover their wings can become saturated with liquid. This weighs a moth down and causes it to become stuck to any nearby surface. In fact, one way to catch moths is to fill a bowl with soapy water and place it under a light source where moths commonly flutter about at night. Since moths are essentially absorptive, they often seek shelter in inclement weather. This can cause moths to enter your home if it is rainy, snowy, or damp outside.