Originally Posted by
Oldguyonoldbike
Something like this works for me down to about 40F. Wool cap with earflaps goes from there down to about 25F:
https://www.walzcaps.com/collections...ap-cycling-cap
A buff works in the same temperature range, and perhaps a bit colder, but I just haven't taken to the buff as I have to the cap with ear flap.
Below that, a balaclava (though this may not apply to SoCal!).