What are the clouds like where you are? When you look upwards can you see great tufts of cotton wool, or do they stretch off into the distance, flat like sheets. Are they dark greys and purples, bringing the promise of rain or maybe there aren’t any at all. For listener John from Lincolnshire in the UK clouds looking up at the clouds is a favourite pastime and he wants to know why they look the way they do and why they are so different from one day to the next. Join Presenter Marnie Chesterton as we turn our gaze skyward to discover what gives clouds their shape. Join us for a cloud spotting mission with Gavin Pretor-Pinney, founder of the cloud appreciation society as he helps us de-code the shapes across the sky to reveal what they can tell us about our atmosphere. Dr Claire Vincent at the University of Melbourne introduces us to one of the superstars of the cloud world, Hector the Convector to explain where thunderstorms come from. And we learn how people like you can help NASA to understand the clouds better with Marilé Colón Robles project scientist at the GLOBE programme. Presented by Marnie Chesterton and Produced by Emily Bird [Image: Dramatic looking clouds. Credit: Getty Images]