Is it doable in winter? Yes, if Mother Nature is being kind.
Even if the weather is amenable that given day, things to consider,
*Run off from snow melt. If you are on the pass, those signs that warn of ICE mean just that.
*Sand strewn by either CalTrans or the roadside grit can git ya.
*Downhill breaking, coming down the summit, is bad for EVERYONE. Might not be your tires that break loose but the speeding cager going by you.
*It can be cold. Really cold. Motorcycles are the apex of wind chill factor.
*...and more.
All that said, I've done it and am still here.