Frost Dates for Calgary, Alberta, Canada

Coordinates: 51.083, -114.083

Growing Season

The last spring air frost in Calgary, Alberta, Canada typically occurs around Jun 8, and the first autumn air frost around Aug 18. This gives a frost-free growing season of approximately 71 days.

USDA Hardiness Zone

This location falls in USDA Hardiness Zone 4b, where the average annual extreme minimum temperature is -31.7 to -28.9°C (-25 to -20°F). This zone rating helps gardeners determine which perennial plants are likely to survive winter.

Temperature Overview

The coldest month is February, with an average low of -12°C (10°F). The warmest month is August, with an average high of 24°C (75°F).

Frost Risk Breakdown

Frost dates at three temperature thresholds: Air frost (0°C / 32°F): Jun 8 (last spring) to Aug 18 (first autumn). Light ground frost (-1°C / 30°F): May 23 (last spring) to Sep 1 (first autumn). Hard ground frost (-2°C / 28°F): May 2 (last spring) to Sep 16 (first autumn).

We predict your growing zone to be approximately ...

USDA Growing Zone: USDA Growing Zone - 4b

... and the frost data for your area is ...

Current Risk Level: Hard Ground Frost possible

for today based on past data only.

We predict a frost free growing season at your location from Jun 8 to Aug 18, which provides approximately 70 frost free days.

For the less tender plants, or if you are planning to protect your plants with fleece etc, your growing season could stretch from May 23 to Sep 1, which provides a total of 101 days for growing.

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