I tested out the Smartwool PhD Run Light Micro socks in two very different environments: a lightning fast flat road race (Canadian Road 5km Championships) and a 12km hilly trail race (Chase the Coyote) in much warmer conditions. In both races, the socks performed brilliantly. They were incredibly comfortable on my feet, even on the technical sections of the trail race, and provided a soft cloud of cushioning for both races. The Smartwool technology is quite fascinating, as they keep the feet dry (I am a profuse sweater, so this is a great feature for me), while climate controlling: my feet were warm for the cooler 5km race, and cool during the heat-wave trail race. The cushioning on the socks is a bit more padded in the bottoms, with a more breathable thickness of fabric on the top of the foot, and the socks overall provided protection from any blister-developing hotspots. Overall, the Smartwool PhD Run Light Micro socks performed beyond expectations, providing a comfortable base for my feet and enabling me to focus on my running! Highly recommended for all kinds of running!