it depends on the humidity and how windy it is.... Personaly I go outside when the rain stops and i gently shake the water off of them... gives me more time to look at em to! but I'm pretty anal about it... it was damp and raining with little sun for about 4 days where i live... now it has been 9 days with great sun and no rain. but there was no sign of mold for the 4 days of rain