This question already has an answer here:
https://meta.stackexchange.com/questions/245302/why-are-people-earning-the-gelt-hat-today - the Gelt hat can be awarded when it's December 16th somewhere. However, Chanukah (my preferred transliteration), being a Jewish holiday, starts at night. That's 25 Kislev on the Hebrew calendar.
If the hat is for Chanukah, it shouldn't be awarded based on the Gregorian calendar. It should be awarded based on the Jewish calendar.