Petersburg, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.9 °F (low) to 65.6 °F (high). Annual precipitation averages 48.3 Inches. Petersburg is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.7 °F | 39.2 °F | 3.55 in. |
| February | 25.4 °F | 44.0 °F | 2.89 in. |
| March | 33.7 °F | 54.4 °F | 4.09 in. |
| April | 44.1 °F | 67.0 °F | 4.93 in. |
| May | 55.1 °F | 76.0 °F | 5.63 in. |
| June | 63.8 °F | 84.2 °F | 4.78 in. |
| July | 66.4 °F | 87.1 °F | 4.28 in. |
| August | 64.3 °F | 86.1 °F | 3.06 in. |
| September | 56.6 °F | 80.9 °F | 3.77 in. |
| October | 45.0 °F | 69.3 °F | 3.49 in. |
| November | 34.9 °F | 54.9 °F | 4.18 in. |
| December | 27.1 °F | 43.6 °F | 3.64 in. |
| Annual | 44.9 °F | 65.6 °F | 48.29 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°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 |