You've posed a question that's been on my mind lately. I'm doing the Bike Tour of Colorado which is the week after Ride the Rockies. Their suggested packing list says waterproof gear. I have the Marmot Precip but I wore it riding once and had the dreaded sauna effect. I also own a water resistant cycling jacket. I'm not sure which one to pack and don't really want to overpack by bringing both.

How heavy are the afternoon showers that they tend to get in Colorado? Do you really need the waterproof as they recommend or is water resistant (and much more breathable) a better choice?