Since 2008, the NHL has expanded outdoor games a lot more than before. The events, usually nationally televised on NBC, are great for media expansion for the league and do very well in attendance.
The most recent outdoor game, February’s Stadium Series matchup between the Pittsburgh Penguins and Philadelphia Flyers at Lincoln Financial Field, home of the Philadelphia Eagles, sold over 69,000 tickets and scored 1.96 million viewers on NBC.
Even Canada has recently expanded outdoors for the Heritage Classic, a matchup between two Canadian teams that score around 25-40 thousand tickets sold in smaller venues to honor players from past renditions of the team.