here's a web page you should bookmark:

http://mthamilton.ucolick.org/techdocs/MH_weather/

up to the minute, weather info, webcams, and highway information. Right now, the webcams seem frozen, the telescope weather stations say it's 32 degrees up at Lick Observatory, and the highway information site says 130 is closed at the Grant Park entrance. I'd probably stick to a ride with a little lower elevation until the road thaws out...