By Julia · weather-canada.com editorial team · Published · 5 min read
A thermometer says what the air is. Wind chill says what your face is about to learn. Environment and Climate Change Canada (ECCC) calculates it from air temperature and wind speed, shows it in forecasts when the temperature is 0 °C or colder and the wind is 5 km/h or more, and groups it into risk levels. This article uses those published hourly values for the airport station of ten cities, from 2016 to 2025, and counts how often each rung of the ladder is reached.
The ladder, as ECCC gives it: from 0 to −9 the risk is low; from −10 to −27 moderate; −28 to −39 high, with exposed skin able to freeze in 10 to 30 minutes; −40 to −47 very high, 5 to 10 minutes; −48 to −54 severe, 2 to 5 minutes; −55 or colder extreme, under 2 minutes. ECCC adds that with sustained winds above 50 km/h, frostbite can happen faster than those times.
How to read the counts
For each day we keep the coldest wind chill value of the 24 hours, then count the days from November to March on which it reached a given rung. So a day with one icy hour before dawn counts as a day. The values are from airport stations, which are open and windy; a downtown street is usually more sheltered. Station records are what ECCC publishes; the counts are ours.
| City | Wind chill −28 or lower (days) | −40 or lower (days) | −48 or lower (days) | Lowest hourly wind chill (°C) and date |
|---|---|---|---|---|
| Iqaluit | 100.2 | 48.3 | 13.6 | −57 · Jan 16, 2020 |
| Yellowknife | 101.8 | 43.9 | 11.6 | −57 · Feb 7, 2021 |
| Winnipeg | 48.3 | 12.0 | 0.3 | −52 · Jan 30, 2019 |
| Edmonton | 36.5 | 9.4 | 1.6 | −58 · Jan 12, 2024 |
| Calgary | 20.2 | 2.5 | 0.0 | −47 · Jan 11, 2024 |
| Montréal | 7.7 | 0.5 | 0.0 | −44 · Feb 4, 2023 |
| Ottawa | 12.4 | 0.7 | 0.0 | −45 · Feb 13, 2016 |
| Toronto | 2.7 | 0.1 | 0.0 | −40 · Feb 13, 2016 |
| Halifax | 2.1 | 0.1 | 0.0 | −43 · Feb 4, 2023 |
| Vancouver | 0.0 | 0.0 | 0.0 | −24 · Jan 12, 2024 |
Environment and Climate Change Canada, hourly observations at each city's airport station (MSC GeoMet, climate-hourly), 2016–2025; wind chill and humidex as published by ECCC; counts by the editorial team.
Rung one: −10, the whole country except one city
Moderate wind chill, −10 or colder, is nearly a permanent condition in the north: 149 days of the 151 from November to March in Yellowknife and Iqaluit. Winnipeg reaches it 130 days a winter, Edmonton 124, Ottawa 99, Calgary 92, Montréal 91 and Halifax 81. Toronto, with 65, is the mildest of the other eight. Only Vancouver stays out, with 7.6 days.
Rung two: −28, where the numbers separate
At −28, ten to thirty minutes to frostbite on bare skin, the cities split into three groups. The north spends about two thirds of the season there: 102 days a winter in Yellowknife and 100 in Iqaluit. The prairies come next: Winnipeg 48, Edmonton 36.5 and Calgary 20 days. The east is far behind: Ottawa 12, Montréal 8, Toronto 3 and Halifax 2. Vancouver has none in ten years.
WinnipegCalgaryMontréal
Environment and Climate Change Canada, hourly observations at each city's airport station (MSC GeoMet, climate-hourly), 2016–2025; wind chill and humidex as published by ECCC; counts by the editorial team.
The chart shows the same count for three cities, winter by winter. Winnipeg ranges from 18 days in 2023–24 to 75 in 2021–22. Calgary stays between 12 (2020–21) and 27 (2016–17). Montréal swings the most in relative terms, from zero days in 2023–24 to 18 in 2021–22. That winter, 2021–22, is the worst of the series in Winnipeg and Montréal and one day short of Calgary's worst (26 days against 27), and it contains the outbreak that crossed Alberta and Manitoba from late December, described in the cold snaps article.
Rung three: −40, a prairie and northern problem
At −40, five to ten minutes to frostbite, the east disappears: Ottawa reaches it 0.7 days a winter, Montréal 0.5, Toronto and Halifax 0.1, which means once in ten years. Calgary has it 2.5 days a winter, Edmonton 9.4 and Winnipeg 12.0. In Yellowknife (44 days) and Iqaluit (48 days) it is a routine part of the winter.
Rung four: −48 and colder, a northern club with two guests
The severe level, two to five minutes, is reached 13.6 days a winter in Iqaluit and 11.6 in Yellowknife. Edmonton gets 1.6 days a winter and Winnipeg 0.3, which is three days in ten winters. Calgary, Ottawa, Montréal, Toronto, Halifax and Vancouver never reached it between 2016 and 2025.
The coldest hours on record, and their dates
The lowest hourly wind chill each station published in the ten years:
- Edmonton, −58, January 12, 2024. Below the −55 "extreme" rung, and the coldest of all ten cities.
- Iqaluit, −57, January 16, 2020.
- Yellowknife, −57, February 7, 2021.
- Winnipeg, −52, January 30, 2019.
- Calgary, −47, January 11, 2024. The day before Edmonton's record.
- Ottawa, −45, February 13, 2016, and Toronto, −40 the same day.
- Montréal, −44, and Halifax, −43, February 4, 2023. One date, two cities hundreds of kilometres apart.
- Vancouver, −24, January 12, 2024. The same day as Edmonton's record.
January 11–12, 2024 therefore hit Calgary, Edmonton and, more gently, Vancouver; February 4, 2023 hit the east. In both cases daily temperature data from the same period show deep cold, with Calgary's lowest minimum of the decade, −39.4 °C, on January 14, 2024 in the reanalysis.
What the counts mean for your clothes
A wind chill of −28 is not a rare day in Winnipeg or Edmonton, where it covers a quarter to a third of the winter, nor in the north, where it covers two thirds. On those days, cover every inch of skin that the wind can touch, and limit the time you spend still: waiting for a bus at the wrong corner is where hours of exposure add up. In Toronto and Halifax, two or three such days a winter mean that you can treat them as an exception and plan around them; in Ottawa, a dozen means you will have a hat, a face cover and mitts ready by December. And a day at −40 or colder is a day to read the forecast, not just the temperature. For clothing by season and region, see when to go, what to wear and how to drive.
Period of the data cited: 2016–2025.