Different fabrics, of course, but different cut ?
If you are asking about suits and sports coat, then the cut is defined by your style & your fit, not really the temperature outside. If you are more fashion forward, then I would advise against slimmer cuts for the summer, unless they are of the thinnest cotton. (I have a nice pair of Helmut Lang white trousers of thin oxford which, albeit slim, are perfect for the summer). Designers usually make baggier clothes for the summer, flare pants instead of tappered, blouses instead of shirts ...etc And, please, none of these Miguel Adrover overpriced ethnic crap. Luc