The people in the scenic area say that July and August are the rutting season for the elks, the most energetic time, and the most worth watching. It would be quite cold to sit in the scenic bus during winter, and the animals might also be afraid of the cold.
Sure, there are reindeer even in winter, just a bit cold when playing.
Winter is possible to go, but it is indeed quite cold, the reindeer are not very active, so it is not very suitable.