The thing to remember, Doug, is that Seattle DOES play outside. CenturyLink Field is an open-air stadium. Granted, we DON’T have the really cold weather that Denver or New England has, but we DO have RAIN....LOTS and LOTS of cold rain. SF has an open-air stadium as well, but their climate is a little milder than ours....and remember that they did pretty well in the frigidity that was Green Bay last week.
The REAL home-field advantage is (IMO) the FANS. Other than the way the team itself plays, they are what make or break a team. Seattle knows they have the backing of the (officially) loudest fans in the NFL. Should the Seahawks make it to the Super Bowl, I think their biggest disadvantage will not be the cold weather...it will be the lack of “The 12th Man”.
I agree, I think the teams are darn near equal in all respects, it will be home field advantage and with extra noise, SF has never been that loud and if they were fans wise the stadium wasn’t.
I bet both sides are working on more non verbal forms of signals.