Used to ride down to 15F or so, but I've realized that no matter the clothing/boots/gloves, I just can't ride more than an hour in cold weather before toes and fingers start to freeze, chest sweat freezes up on the downhills etc. I'll still go out occassionaly if the roads are clear, sun is out and there's little wind, but it's more to get out then for serious exercise. I like to get outside every day ,so hiking and xcountry skiing fill the gaps and get me into the woods as well. I'm lucky in that I can do all of those from my back door or maybe a short drive away and rarely go to a ski center. Love my indoor rower as well.