That was especially true for Garoppolo, who, according to ESPN Stats & Information research, has not thrown a pass in an NFL game with kickoff temperatures below 40 degrees.

By kickoff Saturday night (8:15 p.m. ET), the temperature, according to weather.com, is expected to be around 10 degrees and dropping through the evening, though it's not likely to make the top 10 list of the coldest games.

For point of reference, the last time the 49ers played a playoff game in Green Bay, the kickoff temperature was 5 degrees.

Before Saturday, the closest Garoppolo has come to throwing a pass in what is loosely defined as a "cold weather" NFL game was during his time as the backup to Tom Brady with the New England Patriots.

The Patriots had 13 games with a kickoff temperature below 40 degrees during his tenure, but he played only three snaps in those games, all of which were kneel-downs.

Most recently, that included a pair of FCS playoff games in 2013 that had an average low of 8 degrees on those days.

Coach Kyle Shanahan acknowledged that he doesn't "do well" in cold but said it's up to individual players on how to handle it themselves, whether that means wearing long sleeves, long underwear or whatever else is available to try to keep warm.

"The weather is cold out there, but that's no reason to affect a game," Shanahan said.