So if you didn't know yet, I like to run when it's cold! But I do have my sweet spots. Tuesday night got pretty chilly - upper 20's and windy. My hands were pretty cold at the end. I ended up running with my water bottle tucked under my arm for a while. Last night was just lovely. I think it was upper 20s or low 30s, but no wind. If it's light I'm pretty comfy with low to mid 20's. If it's dark, my sweet spot is low 30's. If I had a limit I would say it's somewhere around zero.
The legs start getting super stiff down around zero. I suppose one could throw enough layers on to run at lower temps but then the weight and bulkiness of your clothes starts hampering motion, and it's just not as much fun. Although...running with extra weight would probably be a great workout, I run because I like to feel free and light! Not because I like to feel like I'm carrying around a small child.
My coldest run, most painful run? Well, coldest-FEELING. It was 9 degrees, not taking into account wind chill, and it WAS windy. Also, it was night. Nick and I ran along the levee for 1 mile to the trailhead, did the 4 mile loop, then headed back on the levee. I never warmed up. My legs burned the whole time. In all fairness to the winter weather, I was wearing extremely lightweight tights. I think Nick and I can both agree that this was our most painful run. He has his own reasons. Maybe having something to do with the fact that he had to stop for a bathroom break?? He loves telling the story. Just ask him.