@Eran Indeed, the most recent one I edited got upvoted shortly before I got the hat.
And now that I think about it, on the other site that I got this hat, there are at least two old posts of mine that I edited and then received upvotes on (during Winter Bash).
@U9-Forward Wait, I got my facts wrong! The hats vanish at UTC 00:00 on Jan 2. In that case, "from the begin" likely means 12 hours after the UTC New Year.
The description of the Glasses With A Number On Top says
post a message in chat within ±12 hours of the UTC New Year's begin that gets starred
But what does this mean?
±12 hours could mean around 12 hours or it could mean 12 hours before and after.
Does the trigger mean around 12 ho...
The Winter Bash chatroom is not linked to a particular site, so there are no hats available for getting a star on New Year's Eve.
IMO, it should be linked to this site (i.e., Meta Stack Exchange).
@AlexanderO'Mara You won't get hats here anyway, as the room isn't parented to a site ;) try the chatroom I linked above... They're always happy to help ;)
From the FAQ
What is going on? Why do I see hats?
From December 12th through January 1st, you'll be able to earn hats all over the sites!
That means that Winter Bash 2018 ends on 2019-01-02 00:00 UTC.