"We've seen it all," Mayer said. "The rain was tracking for game day and that worried us a bit. Rain is not our friend, especially when it gets to 50 or 60 degrees. But right now we're tracking really, really well.
"Now the day before is our practice day. There is some rain in the forecast for the morning, but right now -- and again, it changes by the minute -- it looks like it's heading out in the morning and that also will not be a factor for us."
It is the second time the Winter Classic is being held at Fenway Park, the first time the NHL has revisited a venue for its iconic event. The 2010 Bridgestone NHL Winter Classic was also at Fenway.
"When you walk into this venue, that's our goal, that every fan just says, 'Wow, this is cool,'" Mayer said. "We know this is on a bucket list for a lot of people, but we also know that there's going to be a lot of people here that were here 13 years ago. So, we've got to give them a unique and a new experience. I think we're going to do that."
Mayer said the NHL did significant research to determine that they wanted to shift the orientation of the NHL rink on the field, differing both from what it was in 2010 and what it has been for other Winter Classic events at baseball stadiums.
"The rink orientation is actually quite different. We really wanted to play into the Green Monster," Mayer said. "The rink normally in a baseball stadium goes from third base to first base. Here, we go from -- uniquely -- third base to second base, so we're parallel to the Wall.
"We're really playing into the Green Monster for television and for the fans. It actually gives great sightlines in a baseball stadium. I think it could be something that we'll look at in the future."
In addition to the appearances by former Boston athletes, the Winter Classic will feature performances by The Black Keys, Bell Biv DeVoe singing the U.S. national anthem, and the Boston Pops. The opening ceremony will include Boston Pops conductor Keith Lockhart introducing the two teams as the Boston Pops plays through the introductions, and will continue with other performances throughout the event.
"Admittedly, we're getting to a point where we're going to have to visit some of these incredible ballparks again," Mayer said. "This one was on the top of our list.
"The Bruins are right now playing incredible hockey. This is going to be a great game, the Bruins and the Penguins to start off the new year. Fenway Park. It doesn't get much better than this."