Could be Swedish too, that's very close to an idiomatic expression in Swedish: "there is no bad weather, only bad clothes" ("det finns inget dåligt väder, bara dåliga kläder", it even rhymes in Swedish).
The trick is ample light colored linen clothing that covers as much skin as possible. It might seem counter intuitive to cover your whole arms and legs, but linen is actually very good at evaporating your sweat and keeping you cool while protecting you from the sun.