It's never a good idea to get out in the hills and hope the weather behaves itself. Even the finest days can turn nasty and getting a good soaking is at best a spoiler, at worst it can be life threatening. Solution? Take a waterproof, and if you really want one that packs down small, weighs next to nothing (only 355 grams) and gives superb performance you can't get better than the Mountain Equipment Men's Zeno Waterproof Jacket. The Drilite fabric married with YKK zips that boast both outer and inner storm flaps make a defiant barrier again the most driven rain. Movement is unrestricted thanks to the pre-shaped and articulated sleeves, in combination with an Alpine cut. Keeping the perspiration to a minimum even in a thunderstorm is easy, just open the pit zips and let your body breathe.