Plays in traffic
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
Last year I wore a winter-weight cycling beanie under my regular helmet in temps down to 4°F without a chill. This year I bought one of those super-duper ultra-ventilated jobs, (see my avatar). I was concerned about too much ventilation in the winter. The coldest we've had so far this year was 28°F on Saturday morning. Using the same beanie, there was still not issue with my head getting cold.
One thing many people don't think about is liability. If I sustain a head injury because a car hits me and I'm not wearing a cycling helmet, (even if I am wearing another kind of helmet) a sharp attorney--like the ones the insurance companies use--could argue that I shared responsibility for the injury by being improperly equipped. That could reduce or eliminate payments.
If you still want a less well ventilated helmet for winter cycling, look at cheap ones, or at downhill helmets. Downhill helmets even come in full-face models. I'd avoid helmets intended for non-cycling purposes. They may be as safe or even safer, until you get to a courtroom.