Well, of course, when weather allows it. For example today: it was a confusing mixture between hot sun and windy rains, a switch occurring almost every two hours. A movie lasts usually 2-3 hours so be ready for various surprises. Anyway, the season is officially open and it's a pity to do not take the risk to take a look: with a beer, some popcorn, a colourful blanket, some friends. It's a socially worthy experience, you are feeling at the fullest given the permanent threat we, the Berliners by birth or by choice are permanently living. (the key is two sentences ago)