Sob. Been waiting 40mins to start my Wintersday candy-cane Grind.
So far I've seen theories ranging from "It starts at 12 noon!" to "Press Alt+F4 to start Wintersday!". Some people are also pretending to be Anet employees and talking about power outages and server problems :S
I've also heard 12 noon PST but those could be rumors. ANet should have posted a specific time on their page just like with previous events. I've been in LA for the past 1 1/2 hours running around and partying on the boat which is still going on atm with no "A new build is up" messege popping up so I'm going to bed.