Good point on weather conditions.
I would be kind of surprised if we see Watson play this Saturday night. The daytime temps in Chicago are predicted to be 43, but dropping into the 20's by night. The turf at both Soldier Field and Lambeau are heated, so I doubt playing on frozen surfaces is an issue. I think the footing is more of a concern, as well as playing injured in below freezing temps.
Realistically, the Packers need to win 2 of their last 3 games, to make the playoffs. If the go 0-3, I have zero doubt that they will be eliminated. If they go 1-2, they will be putting their playoff fate in the hands of other teams.
While I would love a home playoff game or 2, going on the road isn't the end of the world. You still have to play well, minimize mistakes, penalties and turnovers or your offseason comes fast.