My knitting choices do change in the summer. 

• I tend to work with plant fibers instead of animal. I will concede that working with wool in said 95 degrees, unless you are in a/c is very unappealing. The one exception is sock yarn. It doesn't feel sticky and hot to me like other wool yarns do.   
• I do tend to crochet. Working with plant fibers can be harder on your hands as there is no stretch to the fiber. The addition of acrylic needles to the market have made a big difference as then bend some. This makes knitting cotton much easier on your hands.  
• I work on smaller projects so I don't have something laying in my lap, no blankets!