Canada's cities are losing up to 19 days of winter

In just the past 10 years, cities around the world, including in Canada, have lost weeks' worth of winter ski, skate and snow days each year due to climate change. They've been replaced by dozens of days of rain, melt and mud, according to a new analysis by Climate Central, a climate research and communications non-profit.

In Canada, some cities and regions that have lost more than two weeks of winter weather, including Vancouver (19 days), B.C.'s Greater Nanaimo region (18 days) and Ontario's Niagara region (15 days).

Toronto has lost 13 days, and even Montreal and Calgary — known for being cold — have lost six and five days below zero, respectively, per year.

Kristina Dahl, vice president for science at Climate Central, said these recent changes are very noticeable because snow turns to rain when the temperature rises above freezing at 0 C.

They may also be quite poignant because winter is a time for cozy holidays in many parts of the world, she added. "Those holidays are times that we remember as children and the traditions that come along with them," she said. "Seeing it warm is almost like losing some of the past."

Climate Central looked at the daily minimum temperatures in December, January and February in 901 cities and 123 countries around the world between 2014 and 2023.

It counted the change in the number of days above zero during that time period, a result of human-caused climate change driven mainly by the burning of fossil fuels.

More than a third of the countries analyzed lost at least a week's worth of winter days during the past decade. The hardest hit — Denmark, Estonia, Latvia and Lithuania — each lost at least three weeks (up to 23 days) of winter days.

Dahl said there were two main reasons some countries and cities were affected more than others. Some, such as Europe (and Canada), are warming faster than the global average.

Many parts of Canada, such as coastal B.C. and southern Ontario, also saw big impacts because their winter temperatures already tend to hover around 0 C.

"So it doesn't take a whole lot of climate change to kick a bunch of winter days ... above that freezing threshold," Dahl added. 

Robert McLeman, director of the RinkWatch project that is tracking outdoor skating rinks in Canada for the 14th season this year, said the biggest change has been in the onset of winter. He thinks the new Climate Central analysis is a "great way for Canadians to recognize that our climate is changing."

The report didn't break down what part of the winter the days were disappearing from. But McLeman, a Wilfrid Laurier University professor who has studied historical records of rink-building, said half a century ago, people were building rinks in Southern Ontario in early December, and ski hills would have plenty of snow to operate before Christmas holidays. 

Today, in mid-December, he said, "I'm looking outside at green grass right now, outside my window in Waterloo, [Ont.]."