Petersburg, Michigan has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.1 °F (low) to 59 °F (high). Annual precipitation averages 34.9 Inches. Petersburg is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.8 °F | 32.0 °F | 2.35 in. |
| February | 17.7 °F | 35.0 °F | 1.99 in. |
| March | 26.0 °F | 44.9 °F | 2.46 in. |
| April | 36.8 °F | 58.2 °F | 3.19 in. |
| May | 48.0 °F | 69.8 °F | 3.92 in. |
| June | 57.7 °F | 79.4 °F | 3.49 in. |
| July | 60.9 °F | 83.4 °F | 3.17 in. |
| August | 59.0 °F | 81.3 °F | 3.44 in. |
| September | 51.6 °F | 75.3 °F | 3.02 in. |
| October | 40.6 °F | 62.6 °F | 2.75 in. |
| November | 31.1 °F | 48.7 °F | 2.77 in. |
| December | 22.9 °F | 37.1 °F | 2.32 in. |
| Annual | 39.1 °F | 59 °F | 34.87 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |