GreenlyCanada: frost dates by city
The average last spring frost and first autumn frost in 7 cities of Canada, from ten years of weather. The last spring frost comes earliest in Vancouver and latest in Calgary.
| City | Last spring frost | First autumn frost | Frost-free days |
|---|---|---|---|
| Vancouver | 27 March | 17 November | 235 days |
| Toronto | 26 April | 30 October | 187 days |
| Montreal | 27 April | 1 November | 188 days |
| Ottawa | 30 April | 1 November | 185 days |
| Edmonton | 7 May | 6 October | 152 days |
| Winnipeg | 12 May | 12 October | 153 days |
| Calgary | 13 May | 1 October | 141 days |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.