Answer:
COLOR in Braille (⠉⠕⠇⠕⠗)
Explanation:
The snowflakes appear to be made of arrows pointing to their centres (as noted by @RonchenLuo) suggesting that we should focus on the centres (as suggested by Hint 1). Indeed, the centres form the dots in Braille script (the one with 3×2 grid of dots for each letter) which then spell the word COLOR as shown in the image below. I am still not sure what the relevance to Christmas is.
