to answer this with an official quote:
https://forum-en.guildwars2.com/foru...rst#post980889Hi,
For the Wintersday content, do you need to be level 80 to participate effectively?
If not, are there any level appropriate rewards for non level 80s?
Cheers.
No, you can be any level to participate in any of the main stage Wintersday content. And yes, there are both level-appropriate and level independent rewards.