Originally Posted by mdilthey

My Marmot Super-mica went unused when it rained on one of our biking days. Why, you ask?

Backpackers deal with this issue all the time. One of my comrades was a Long Trail/AT Veteran. When it began to rain and he saw me getting on my raincoat, he said "What are you doing? That's for camp."

Instead, I had my Merino Wool bike pants, my Under Armour t-shirt, and Merino Wool Arm Warmers from Smartwool. Water beaded up on the outside of the wool and eventually soaked in, but warmth was retained and 10 minutes after the rain stopped, I was completely dry. My best rain option has been to use my raincoat when my tent needs adjusting mid-storm, but for actual riding, merino wool is king.