I live in a warm climate. The weather is sporadic, and in winter it will drop down to around 40 degrees then spike to 75 or 80 the next. It doesn't get too cold, but it can at nights during the dead of winter. No snow, but cold rains. I need a light weight sheet that is waterproof. Being a teenager, I am obsessed with bright colors, but I am not picky. Does anyone have any suggestions for a good light weight sheet that is not too expensive. Also, my horses measure 68 inches and 64 inches, could the smaller one use a yearling sheet? Most yearlings measure 60 to 68 inches.