NHL Green essay: Outdoor rinks at risk despite cold winter of 2024-25

As part of the NHL Green initiative celebrating Green Month in April, NHL.com will feature stories on how the NHL is looking to grow and protect the game of hockey and its communities for generations to come. Today, Robert McLeman from Wilfrid Laurier University and the RinkWatch Project, writes about this year’s outdoor rinks. NHL Green and RinkWatch have been working together since 2016 with a common of goal of protecting our game and planet for future generations.

The U.S. National Oceanic and Atmospheric Agency recently announced that 2024 was the hottest year since reliable records first started being kept in the 1850s. In fact, the 10 hottest years ever recorded all have occurred since 2014. But if the world is getting so hot, why was the winter of 2024-25 such a good one for outdoor skating rinks?

Me and my colleagues at Wilfrid Laurier University have been gathering skating reports from outdoor rinks (ODRs) across North America since 2013 through the RinkWatch citizen science project. This past winter, most of our participants -- especially ODR makers in eastern North America -- told us they had the best skating season in many years. A cold spell in mid-January 2025 saw people building ODRs in South Carolina and Tennessee -- states with great NHL fans, but not areas we associate with outdoor skating. We also saw ODRs popping up in areas of Atlantic Canada and the northeastern United States that hadn’t seen outdoor skating in several years. In more reliably cold areas like western Canada, northern Ontario and northern Quebec, ODRs were skateable well into March and even early April.

The Palermo family in Fort Mill, South Carolina was able to create a backyard rink this past January. Photo by the Palermo family

In Waterloo, Ontario -- home to Laurier and located centrally in hockey-loving southwestern Ontario -- sub-freezing temperatures took hold on New Year’s Eve and stayed with us, uninterrupted, until mid-March. The skating was fantastic. It was a huge improvement from the previous two winters, when temperatures were mild and fluctuated wildly. Hockey fans and ODR enthusiasts will remember that January 2023 was so mild, the world’s largest outdoor rink, Ottawa’s Rideau Canal Skateway, never opened, and only a handful of skating days were eked out the following winter. In January 2024, the finals of the U.S. Pond Hockey Championships in Minnesota had to be canceled.

This past winter was not especially cold by historical standards. As shown in this chart, average January temperatures in 2025 were only slightly colder than the 50-year average. And the 50-year average is itself misleadingly warm, because it is being skewed by multiple mild Januarys during the last decade. Back in the 1970s -- when the Montreal Canadiens won the Stanley Cup six times and the Boston Bruins and Philadelphia Flyers each won two titles -- average January temperatures in Waterloo were more than 2.5 degrees Celsius colder than the past decade. As January temperatures become milder and more erratic, pond ice becomes treacherous and building a decent ODR becomes difficult.

RinkWatch data shows that the number of winter days cold enough to build ODRs is shrinking, especially in eastern North America, where winter temperatures generally are milder than in the west. When a moderately cold winter like 2024-25 comes along, we perceive it as being exceptional, even though it is merely average in the historical sense. This is something known as “recency bias,” a tendency for people to better recall (and place more importance on) recent events than less recent ones. It presents a challenge for scientists trying to explain climate change and global warming to the public. When scientists describe how the last decade was the hottest on record, people may be tempted to shrug and say, “If the world is getting hotter, why was it so cold this winter (or why was the skating so good)?” But the reality is that winters with temperatures cold enough for good outdoor skating are becoming fewer and farther between. The great skating we had this past winter is a reminder of what we stand to lose if we fail to reduce greenhouse gas emissions.

What would the loss of outdoor skating mean for the sport of hockey? According to former NHL player and now NHL executive Kevin Westgarth, “Outdoor rinks aren’t just places to play hockey -- they are where our love of the game is born, where we deepen friendships with frozen toes, and make memories we hope to share with the next generation. Losing the frozen ponds, losing playing under the open skies would mean losing the purest form of our sport, the very heart of what makes hockey so special.”

Kelly Paton, Laurier’s women’s hockey coach and Ontario University Athletics coach of the year explains that outdoor rinks, “… provide unique environments where creativity thrives. The less predictable conditions, uneven ice and varying rink sizes force players to adapt and think on their feet, encouraging them to explore new techniques and strategies. This freedom has a positive effect on their decision-making skills and allows them to develop a more creative approach to the game. It gives players space to improvise and experiment, and they develop a deeper understanding of the game, improving both their individual skill and overall hockey IQ."

Kelly Paton gives instructions to the Laurier University women’s varsity hockey team. Photo by Laurier University

And what would the loss of outdoor skating mean for everyone who loves the activity for its own sake? To Shelley Jackson, longtime RinkWatch participant, “Skating outside in the winter is a rite of passage. It would mean the loss of a child's opportunity to have that free, innocent, creative play on the ice, where nothing matters but wearing your idol’s sweater, battling the winter elements and living out that Game 7, Stanley Cup-winning goal with friends in the backyard, and believing you can be the next Sidney Crosby.”

Ian Williams, an ODR-maker and youth hockey coach said, “We'd lose the unstructured joy of skating where the ice crackles, the air is crisp and the game feels free and magical. We would lose a timeless Northern winter tradition that brings friends and communities together.”

Ian Williams and teammates at the Lake Placid 2025 CAN/AM Pond Hockey tournament. Photo by Ian Williams