Originally Posted by
jrickards
I question the temperature ratings. For example, the full boot (but lightest insulated) Japanther is rated down to -3C, I wore my summer cycling shoes with long wool socks inside down to -5C or so this past November/December (I must admit that I was a bit surprised as to how comfortable I was without booties). If I were to purchase the Japanther, I'd likely purchase them large enough to comfortably wear wool socks in them and I'd probably be fine down to about -15C or maybe colder.
Different people have such different levels of comfort, it's got to be rather difficult to be able to post a temp range that's true for everyone. Even if you don't have something crazy like Renaud's disease, it varies - a lot.
I was riding at 18F (-8c) recently, wearing uninsulated Chrome Kurk's (and not even the waterproof ones) with thick wool socks (don't remember the brand, the thickness was 3/5 on their scale) and was very warm. Surprisingly warm. I had worn them thinking "I bet my feet will be cold and I'll need to go out and buy more insulated shoes". Instead they were toasty warm.
I think that what would work for one person at -3C would be freezing cold for another person, and very almost overly warm for someone else. So it's hard to give an accurate range.