Michael Raupp - Professor of Entomology at the University of Maryland, USA
There's nothing more a butterfly has to do on a rainy day than to hide from the rain. For a monarch butterfly, which weighs only 500 milligrams, a storm is no small matter: it gets hit by a 70-milligram drop of rain, which could be the equivalent of two waterballs weighing as much as a small bowling ball hitting you and me.
The storm also hinders the butterfly's movements. To prepare for flight, these aerial aerobatic pilots have to let the sunlight hit their wings directly, because only then can they warm their flight muscles (wing muscles) quickly, and cloudy skies block the solar radiation necessary for them to take off.
So when the clouds are dark, butterflies look for shelter in their habitats: places like tall grasses or leafy plants that provide shelter from the wind and rain. When the sun reappears, they are often back in the sky within minutes, looking around for fun.
Also, you don't have to worry if a butterfly does get caught in the rain, because a butterfly's wings are made up of hundreds of tiny scales, similar to those found on fish. They also shield them from the rain when it rains so they don't get really wet.