How can you keep your cat from shedding during the spring and summer months? You can't. Get over it. Your cat will shed, no matter what. It's a normal part of kitty life. Part of the joy of cat ownership is the joy of flying fur. It's on my clothes, on my bed, and periodically, in a lovely hairball clump on my carpet.
However, you can reduce the amount of shedding and the severity of it by brushing your cat every day. The greatest thing EVER for the warm months is an undercoat brush. I had never seen one of these until we made a vet visit one day, and the vet tech brushed my cat with this weird mutant looking device. It was amazing! It reaches not only the top layer of fur but also the undercoat which is much thicker and seems to be what Kitty swallows and chokes on. It's a terrific device. This is my undercoat brush: http://grooming.petedge.com/Oster-Pet-Grooming-Rakes-OS790.pro but there are many styles and types to choose from. Used daily, together with a regular cat brush to catch all the loose flying fur, you'll find a substantial reduction in cat fur around your home.
Another fun trick to reduce your flying fur problem is to wipe your cat down. This also reduces loose fur floating around. I use Swiffer dusters, those fun fluffy things you're supposed to use to dust your home - instead, I use it to dust my cat! It doesn't catch a lot of loose fur but it definitely gets some of it up and off of Kitty, and he loves the whole Swiffer experience.
Got any other great tips to reduce your cat's shedding? Let me know!