Despite her looks, Holly isn't just a seasonal character!
The entire concept behind her is that she's a Water Elemental infatuated with the idea of Christmas and other festive winter celebrations. As a result, she uses her magic to freeze herself into snow, wearing festive attire and accessories to go along with the look.
Despite being cool to the touch, she has a warm personality and is keen on hugs and displays of affection, as well as indulging in all manner of festive activities, even out of season if she can get away with it!
Although being frozen like she is makes Holly slower and less agile than her kind normally are, she greatly enjoys being this way, and becomes frustrated or upset whenever she 'melts' back into her natural, liquid form. Thankfully, it takes quite high temperatures to force her back into liquid form, or people interfering with her magic.