In this episode Joel has a bad physiological/psychological reaction to several consecutive days of sun taking place in that part of Alaska. If this is true, then, for the Christmas episode in season 3 ("Seoul Mates" 3.10) there should have been no sun or almost no sun during the episode.
After Joel gets his whistle, he blows it with the neck strap in his hand. When the scene changes, he's wearing the neck strap.