I've done my 22 mile round trip journey in mid teens with wind chills in the single digits. It really does not get much colder in the DC area than that. I've dialed in my clothing so that that this can be mostly pleasant for the hour or so that it takes. However, I still cannot keep my right foot warm, even with Descente front foot covers, doubled up socks, and a chemical warmer, my two big toes on my right foot still get cold sometime. As much as I hate to, if I cannot find a better solution to keep my feet warm, I may have to only commute when it is in the 30s.