Frost Dates for Ann Arbor, Michigan, United States of America

Coordinates: 42.271, -83.726

Growing Season

The last spring air frost in Ann Arbor, Michigan, United States of America typically occurs around May 3, and the first autumn air frost around Sep 19. This gives a frost-free growing season of approximately 139 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 27°C (81°F).

Frost Risk Breakdown

Frost dates at three temperature thresholds: Air frost (0°C / 32°F): May 3 (last spring) to Sep 19 (first autumn). Light ground frost (-1°C / 30°F): Apr 24 (last spring) to Sep 28 (first autumn). Hard ground frost (-2°C / 28°F): Apr 12 (last spring) to Oct 12 (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 3 to Sep 19, which provides approximately 138 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 24 to Sep 28, which provides a total of 157 days for growing.

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
  • Hard Ground Frost possible
  • Light Ground Frost possible
  • Air Frost possible
  • Safest (unlikely)
First and last frost dates by frost type
FirstLast
Air FrostSep 19May 3
Light Ground FrostSep 28Apr 24
Hard Ground FrostOct 12Apr 12

Frost Dates for Ann Arbor, Michigan, United States of America | FrostDates.com