My husband being a fireman has seen a lot of wrecks and casualties, a lot of the times it is during bad weather that is a factor second to driving while impaired. Needless to say he is meticulous when it comes to our autos, he checks the air pressure, wiper blades, fluids, filters, tire tread and so on. He has religiously used a product called Rain X, he gets it at Wal-Mart. They have some that goes into your windshield fluid reservoir, but the one we currently have is a spray bottle, it is 16 fluid ounces, much like a Windex.
You spray it on and make circular motions with a damp cloth, you allow it to dry to a dull haze the wipe off. The first time it rains you will notice a difference, so much so that at times when it rains you do not have to run your wiper blades!
He repeats this about once a month and it works very well for us. The bottle claims it repels sleet and snow as well, but we do not see much of either of those here.
Another thing I love about this product is it is made right here in The United States of America!
Keep in mind this product does contain harmful agents such as alcohol so keep out of reach of young children and your pets. I recommend this product to everyone who drives.