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Frost Dates for Naperville, Illinois, United States of America

Coordinates: 41.786, -88.147

Growing Season

The last spring air frost in Naperville, Illinois, United States of America typically occurs around Apr 26, and the first autumn air frost around Sep 26. This gives a frost-free growing season of approximately 153 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 28°C (82°F).

Frost Risk Breakdown

Frost dates at three temperature thresholds: Air frost (0°C / 32°F): Apr 26 (last spring) to Sep 26 (first autumn). Light ground frost (-1°C / 30°F): Apr 18 (last spring) to Oct 4 (first autumn). Hard ground frost (-2°C / 28°F): Apr 3 (last spring) to Oct 17 (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 Apr 26 to Sep 26, which provides approximately 152 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 18 to Oct 4, which provides a total of 169 days for growing.

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