Agreed that 9-10C is fine, and perhaps even ideal, for a marathon. But that's definitely NOT the case if it's raining, as it clearly was in this race. Water in the air, covering your skin, puddling on the ground, and soaking your clothing and shoes has a big effect on thermoregulation, comfort, and even shoe efficiency. A light sprinkle and a bit of misting is okay, but no one running a long distance welcomes outright rain.[/quote]
Call me crazy, but 50F and raining is one of my favorite conditions to run in, especially for longer distances. I tend to generate a ton of heat when I exercise so I find that rain and cool temperatures prevents me from overheating, which is often my limiting factor when running longer distances.