Canadian Gardening Data — A Free Climate Knowledge Base
Open, citable Canadian growing-season data for gardeners, writers, garden clubs, educators and researchers — frost-free season length for 38 cities, aggregated by province and by plant hardiness zone, from Environment and Climate Change Canada climate normals (1991–2020). Free to use with attribution.
At a glance: Across 38 Canadian cities, the frost-free growing season runs from 109 days in Sudbury to 280 days in Victoria — a 171-day national spread, with a median of 160 days. Coastal British Columbia has the longest seasons in the country; the Prairies and northern Ontario the shortest. Source: Environment and Climate Change Canada climate normals, 1991–2020. Free to cite with a link to this page.
📥 Download the dataset
The full 38-city table — last frost, first frost, frost-free days, hardiness zone — as a free CSV.
Download CSV →📝 How to cite this data
Canadian frost-free season data: ECCC climate normals (1991–2020), compiled by GrowersGuide.ca
Frost-Free Season by Province
The growing season across 38 Canadian cities, summarised by province — the shortest and longest frost-free season in each, plus the provincial median. All figures are frost-free days (the average number of days between the last spring frost and the first fall frost).
| Province | Cities | Shortest season | Longest season | Median (days) |
|---|---|---|---|---|
| British Columbia | 9 | Kamloops — 158 days | Victoria — 280 days | 240 |
| Alberta | 4 | Red Deer — 117 days | Lethbridge — 136 days | 127 |
| Saskatchewan | 2 | Saskatoon — 110 days | Regina — 119 days | 115 |
| Manitoba | 1 | Winnipeg — 118 days | Winnipeg — 118 days | 118 |
| Ontario | 13 | Sudbury — 109 days | St. Catharines — 196 days | 179 |
| Quebec | 3 | Québec City — 134 days | Laval — 165 days | 151 |
| New Brunswick | 3 | Fredericton — 132 days | Saint John — 153 days | 136 |
| Nova Scotia | 1 | Halifax — 161 days | Halifax — 161 days | 161 |
| Prince Edward Island | 1 | Charlottetown — 157 days | Charlottetown — 157 days | 157 |
| Newfoundland & Labrador | 1 | St. John's — 142 days | St. John's — 142 days | 142 |
Frost-Free Season by Hardiness Zone
The same 38 cities grouped by their primary plant hardiness zone (Natural Resources Canada), warmest to coldest. This shows the real relationship between zone and season length — warmer zones consistently deliver a longer frost-free window. Cities that straddle two zones are grouped by their warmer (primary) zone.
| Hardiness zone | Cities | Frost-free range (days) | Example cities |
|---|---|---|---|
| Zone 8b | 3 | 240–280 | Nanaimo, Vancouver, Victoria |
| Zone 8a | 4 | 204–245 | Abbotsford, Burnaby, Chilliwack… |
| Zone 7a | 1 | 191 | Windsor |
| Zone 6b | 6 | 158–196 | Kamloops, Kelowna, Hamilton… |
| Zone 6a | 8 | 153–180 | Saint John, Halifax, Brampton… |
| Zone 5b | 5 | 132–151 | Fredericton, Moncton, St. John's… |
| Zone 5a | 3 | 126–156 | Lethbridge, Barrie, Ottawa |
| Zone 4b | 3 | 109–134 | Red Deer, Sudbury, Québec City |
| Zone 4a | 1 | 132 | Edmonton |
| Zone 3b | 3 | 110–121 | Calgary, Regina, Saskatoon |
| Zone 3a | 1 | 118 | Winnipeg |
The Full City-by-City Data
These summaries are built from the full per-city dataset. For the complete table — every city's exact last frost, first frost, frost-free days and zone, sortable, with an embeddable widget — and the cities ranked from longest to shortest season, use the two reference pages below.
Methodology & Sources
- Frost dates are average last spring frost and first fall frost, based on Environment and Climate Change Canada climate normals for the 1991–2020 reference period.
- Frost-free days is the average number of days between the last spring frost and the first fall frost — a practical measure of growing-season length. Individual years vary around these averages.
- Hardiness zones follow the Natural Resources Canada Plant Hardiness Zone system (planthardiness.gc.ca), which differs from the USDA system used by most US sources.
- The province and zone aggregates on this page are computed directly from the published city dataset, so they always match the downloadable CSV.
- Caveat: frost dates are microclimate-sensitive — elevation, proximity to water, and urban heat islands shift them within any city. Treat the figures as regional averages, not guarantees for a specific garden.
For researchers, journalists, garden clubs & educators
This data is free to use, quote and republish — in articles, newsletters, class handouts, master-gardener materials, or your own site — provided you credit GrowersGuide.ca with a link to this page. If you'd like the figures in another format (a specific province, a custom city list, or a different cut), or want to check a number before you publish, get in touch at zusashicanada@gmail.com.
Every figure here is traceable to the source CSV and Environment and Climate Change Canada climate normals — we'd rather you cite it correctly than approximate it.
Use of This Data
The compiled dataset and aggregates on this page are free to use with attribution to GrowersGuide.ca (a link to this page is sufficient). The underlying climate normals are the work of Environment and Climate Change Canada, and the hardiness-zone framework is from Natural Resources Canada; please credit those primary sources when the context calls for it. Provided as-is, without warranty — verify against ECCC directly for any critical or commercial use.