Frost Dates for London, Ontario, Canada

Coordinates: 42.983, -81.250

Growing Season

The last spring air frost in London, Ontario, Canada typically occurs around May 7, and the first autumn air frost around Sep 19. This gives a frost-free growing season of approximately 135 days.

USDA Hardiness Zone

This location falls in USDA Hardiness Zone 5b, where the average annual extreme minimum temperature is -26.1 to -23.3°C (-15 to -10°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 -8°C (18°F). The warmest month is July, with an average high of 26°C (79°F).

Frost Risk Breakdown

Frost dates at three temperature thresholds: Air frost (0°C / 32°F): May 7 (last spring) to Sep 19 (first autumn). Light ground frost (-1°C / 30°F): Apr 28 (last spring) to Sep 29 (first autumn). Hard ground frost (-2°C / 28°F): Apr 13 (last spring) to Oct 14 (first autumn).

We predict your growing zone to be approximately ...

USDA Growing Zone: USDA Growing Zone - 5b

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

Current Risk Level: Light Ground Frost possible

for today based on past data only.

We predict a frost free growing season at your location from May 7 to Sep 19, which provides approximately 134 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 Apr 28 to Sep 29, which provides a total of 154 days for growing.

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