Frost Dates for Sudbury, Ontario, Canada

Coordinates: 46.500, -80.967

Growing Season

The last spring air frost in Sudbury, Ontario, Canada typically occurs around May 19, and the first autumn air frost around Sep 7. This gives a frost-free growing season of approximately 111 days.

USDA Hardiness Zone

This location falls in USDA Hardiness Zone 4a, where the average annual extreme minimum temperature is -34.4 to -31.7°C (-30 to -25°F). This zone rating helps gardeners determine which perennial plants are likely to survive winter.

Temperature Overview

The coldest month is January, with an average low of -16°C (3°F). The warmest month is July, with an average high of 24°C (75°F).

Frost Risk Breakdown

Frost dates at three temperature thresholds: Air frost (0°C / 32°F): May 19 (last spring) to Sep 7 (first autumn). Light ground frost (-1°C / 30°F): May 8 (last spring) to Sep 19 (first autumn). Hard ground frost (-2°C / 28°F): Apr 23 (last spring) to Oct 6 (first autumn).

We predict your growing zone to be approximately ...

USDA Growing Zone: USDA Growing Zone - 4a

... 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 May 19 to Sep 7, which provides approximately 110 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 8 to Sep 19, which provides a total of 134 days for growing.

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