Who knew there were so many of us? warm weather,, indoor on trainer, or summers: headsweats (I burn just thinking about UV, so I never ride /wo one - no leopard spots for me!). Cooler - a skullcap (either one ProBikeKit sells or a Sealskinz). Colder - a lined under-helmet cap (whatever performance had on sale). Freezing or need face covering - unlined balaclava. Really cold - lined balaclava. Also combos of all of the above (unlined balaclava and the Sealskinz seems good from mid 20s up for at least an hour).