Conifer Wurm

• WWizards of the Coast2019-06-14
  Official Ruling
  Because Conifer Wurm is itself a snow permanent, its ability will usually give it at least +1/+1.
• WWizards of the Coast2019-06-14
  Official Ruling
  The value of X is determined only as Conifer Wurm's ability begins to resolve. It won't change later in the turn if the number of snow permanents you control changes.

Rulings via Scryfall