Once it goes below 0*F I start to question it. I have gone colder when I am feeling brave, but much lower and I start to have some problems. My hands won't stay warm below 30* no matter what gloves I am wearing. Anything below 15* and they will be numb in less than 5 minutes, so they are always my limiter. It's funny cause I can get away with a baselayer, thin shell, jeans and wool socks and still be toasty. No coat, goggles or any of that. I really think I might need those heated gloves.