Another vote for a Buff!! I have been wearing it in the winter weather (and pulling it down over my ears) and it's great. It fits under the helmet easily.

I also wore it all summer to tame my wild curls under my helmet and it was great. I'd wet it down, put it over my hair and it kept me cool in 100 degree heat.

Buff's are AWESOME!! (LL Bean sells the polar version that has fleece on one end...Terry sells a few styles...REI carries them....) Now...if only TE would start carrying them, I'd be all set! *hint, hint*