Originally Posted by
Marcus_Ti
I have a Pearl Izumi "Barrier" one is only good on its own to 5C....a merino wool one that is good down to just below freezing...and below that I layer them.
Actually, I sometimes have to put on a second layer on my face, like when it gets down to -20C. The one that I normally wear is a synthetic one, and is great all around up to about that temperature, but colder than that I feel like it's necessary to add an extra fleece layer that also covers the neck more.
When the temp gets down that low, sweat is no longer an issue. I'm not riding hard enough to produce sweat or generate heat, so layering is essential.