Canadian Plant Hardiness Zones with Seven Climate Variables

Plant hardiness zones for Canada are defined by a formula using seven climate variables influencing perennial plant survival. The 4th edition map was developed by scientists from Natural Resources Canada, Environment Canada, and Agriculture and Agri-Food Canada using climate averages from 1991 to 2020. It updates a previous version based on data from 1930 to 1960.

Use Cases

• Classify geographic zones for plant survival using the seven climate variables: monthly mean minimum temperature of coldest month, mean frost-free period, June-November rainfall, monthly mean maximum temperature of warmest month, winter harshness index, mean maximum snow depth, and maximum wind gust.
• Compare the multi-variable hardiness zones against the alternative single-variable map based solely on average extreme minimum temperature for the same 1991-2020 period.
• Analyze temporal shifts in plant hardiness by comparing zone classifications derived from 1991-2020 climate averages with those from the original 1930-1960 period.
• Model regional suitability for specific perennial crops by correlating hardiness zone classifications with local climate variable thresholds.

Strengths

• Map is based on a formula using seven specific climate variables, providing a multi-faceted model for plant survival.
• Data uses updated 30-year climate normals from 1991 to 2020, replacing older 1930-1960 averages.
• Development involved a collaborative effort by scientists from three Canadian federal government departments.

Limitations

• The dataset's spatial resolution and specific row/feature counts for the underlying grid data are not provided.
• Sample data and column definitions are unavailable, limiting immediate analysis of the raw model inputs.
• The primary output is a map; access to the raw, tabular climate data used to generate the zones may be restricted.

Provenance

Source

Natural Resources Canada's Canada Centre for Mapping and Earth Observation, in collaboration with Environment Canada and Agriculture and Agri-Food Canada.

Collection Method

Derived from a formula applied to climate normals, including variables like temperature, rainfall, snow depth, and wind.

Time Range

Climate averages for the period 1991 to 2020; original map reference period is 1930 to 1960.

Freshness

Data reflects climate averages up to 2020 and was last updated in April 2026.

Geography

Canada