Practical planning tools for short growing seasons.

Map-style climate resource

Canada Garden Climate Atlas

A visual guide to frost-free days, seasonal crop heat, and short-season gardening pressure across Canadian cities.

Updated 2026-05-28 · 178 Canadian cities with both frost and GDD reference data.

Median frost-free season 134 days Median across the Canadian cities in the table.
Median base-50 GDD 1382 Median seasonal heat accumulation across Canadian cities.
Core lesson Time ≠ heat A longer frost-free season does not always mean a warmer crop season.

Outdoor window

Frost-free days show how long tender crops usually have outside.

A short frost window pushes gardeners toward fast varieties, transplants, protection, or conservative crop choices.

Crop heat

GDD shows how much warmth accumulates inside that window.

Warm-season crops such as tomatoes, peppers, squash, corn, and melons need more than a late frost date. They need usable heat.

Climate point map

Canada frost-free season by city

Points are positioned by city latitude and longitude. Darker/larger points represent longer frost-free windows.

Very short Under 100 days Short 100–129 days Moderate 130–159 days Long 160–189 days Very long 190+ days

Climate point map

Canada base-50°F GDD by city

Same city positions, different signal. Darker/larger points represent higher seasonal heat accumulation.

Very cool Under 1,000 base-50 GDD Cool 1,000–1,499 Moderate heat 1,500–1,999 Warm 2,000–2,499 High heat 2,500+

Climate leaders and pressure points

The fastest read is often in the extremes: which places have the most outdoor time, which places are most compressed, and which places accumulate the most usable crop heat.

Provincial and territorial summary

Median values are calculated from the Canadian cities in the table.

Region Cities Median frost-free days Median base-50 GDD Longest-season city Highest-GDD city
Alberta 29 115 912 Spruce Grove Fort McMurray
British Columbia 29 169 1099 Vancouver Nelson
Manitoba 12 122 1135 Winkler Portage la Prairie
New Brunswick 6 132 1294 Fredericton Miramichi
Newfoundland and Labrador 3 142 1579 St. John's Corner Brook
Northwest Territories 2 93 363 Yellowknife Yellowknife
Nova Scotia 8 132 1311 Halifax Bridgewater
Ontario 51 159 1932 Windsor Sioux Lookout
Prince Edward Island 2 154 1504 Charlottetown Summerside
Quebec 22 138 1432 Montreal Baie-Comeau
Saskatchewan 13 115 1036 Swift Current Estevan
Yukon 1 86 1474 Whitehorse Whitehorse

How to use the atlas

Frost-free days estimate the outdoor window for tender crops. Base-50°F GDD estimates how much crop heat accumulates during the season. For warm-season crops, the best planning read comes from comparing both signals together.

  • Use the frost-free map to compare outdoor season length.
  • Use the GDD map to compare seasonal heat for crops such as tomatoes, peppers, corn, squash, and melons.
  • Use Long Season vs Warm Season to understand why the two signals are not interchangeable.

Share, cite, or reference this atlas

Use the atlas when writing about Canadian garden climate, frost-free season length, growing degree days, or short-season crop planning.

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Methodology and limits

This atlas joins city frost-date records with base-50°F GDD reference records. Frost-free days are calculated from average last spring frost and first fall frost. GDD values represent seasonal accumulated crop heat from the mapped station series. These values are planning averages, not site-specific forecasts.

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