The forecast Sunday calls for partly cloudy skies with highs in the low 20s. That's downright balmy compared to the arctic front that encased Green Bay at midweek, when temperatures hovered near zero.
To top it off, a snowstorm that was supposed to dump 3 to 4 inches of snow on the area started just before practice began Thursday, forcing McCarthy to move the team indoors for the whole session.
It warmed up, but only slightly, which was fine by McCarthy. The Packers were even able to get the temperature inside the facility to about 22 degrees, which would be roughly the high temperature for Sunday.
"I feel like we got done what we needed to get done these two days," McCarthy said. "We were able to get the wind direction changed, so we felt like it was pretty close to what the conditions will be that we're playing in on Sunday."
Though not nearly as cold as when the teams last met in Green Bay in the postseason — the 1967 NFL championship dubbed the Ice Bowl after being played in brutally cold conditions.
It was minus 13 for that game at kickoff. It's not supposed to be that chilly this weekend, though it's not exactly weather familiar to some Cowboys, either.
According to STATS, the Cowboys are 11-13 since 1991 in games played in with the temperature lower than 40 degrees. Their most recent game in that category: Dec. 4, when Dallas beat Chicago 41-28 at Soldier Field.
"It comes down to what is your resistance to the cold, how much can you tolerate it,"Cowboys cornerback Brandon Carr said. "This game, this time of the season, get comfortable. ... Just be comfortable to be at your best."
For defensive end Jeremy Mincey, that means sticking with his usual routine of wearing sleeves.
Packers guard T.J. Lang said he's going with "extra-long elbow sleeves,' while receiver Davante Adams is going with bare arms.
"No sleeves. Never sleeves," the Packers rookie said. "Yeah, we don't wear sleeves in the wideout room."
But there is more to preparation than making fashion choices.
Carr said it's important to be "fast and light." He wants to stay warm without wearing too many layers. He'll check the condition of the heated field before the game for footing.
"Bring multiple pairs of clears out, detachables, nubs, long studs, short studs, whatever," Carr said. "Just check the field and the footing and see if it's soft or it can hold up to up to the studs."
Dallas, 8-0 on the road this season, clearly plays well away from home no matter the conditions. McCarthy downplayed any talk of having a cold-weather advantage.
"I think football's football. I'm not counting the weather," he said.
One Cowboy familiar with Midwest winters is quarterback Tony Romo, who grew up in Burlington, in southeastern Wisconsin, and played college ball at Eastern Illinois.
Romo is 3-5 as a starter in games played when the temperature dipped below 40. Don't forget that the Cowboys also play in cold weather late in the season if they have road games against NFC East rivals New York, Philadelphia and Washington.
"It can affect you if you haven't played in it before and if you're not prepared," Romo said. "For us, we'll just put our head down and go to work, like we always do."