When winter arrives, perspiration becomes a serious issue which can rapidly chill the body unless managed properly. In particular, when I climb 1300 vertical feet (repeatedly), I sweat plenty, no matter how I’m dressed or how cold it is. Descending, all that sweat had better be off my skin, or I’m a chilled goose.
Base layer under the upper body layers
The OutWet base layer has delivered a more comfortable ride for me than anything I’ve used before.
The OutWet base layer keeps that cold sweat off my skin— it really works. It won’t hide the feeling of having sweated entirely, but I don’t feel clammy wet as with some jerseys, and it definitely helps keep me warmer by keeping cold sweat off my skin.
On my head
On my head, I find that an IbexWear 'Zephyr' merino wool beanie fits great under my Lazer Genesis helmet (not true of most other helmets designs I’ve tried). This is a BIG DEAL for me: this is the first helmet with which I can comfortably wear a thin wool hat under the helmet. No longer do I have to suffer a headache from a poor fit as with other helmets.
The IbexWearwool cap “beanie”, 'Coppi' Merino cycling cap and Skimmer are all quite similar, but one might fit better than another, so try more than one.
The 'Zepher' cap has seriously raised my comfort level in colder conditions; being semi-bald, a wet head can lose a great deal of body heat very quickly.
On the legs
In our California “winter”, the Pearl Izumi Elite ThermaFleece cycling tight is enough for most days (I use the thicker and warm AmFib tight when the temps go below about 48° F). It’s very important to keep the knees (patella) warm during cold weather; there isn’t much blood flow to that area. My knees start to ache if they get cold, so I prefer to wear tights below about 60° F.