Petersburg, Kentucky has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.9 °C (low) to 18.4 °C (high). Annual precipitation averages 1147.8 Millimeters. Petersburg is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.8 °C | 4.3 °C | 85.09 mm |
| February | -3.7 °C | 6.6 °C | 72.39 mm |
| March | 0.5 °C | 11.9 °C | 101.6 mm |
| April | 6 °C | 18.9 °C | 118.87 mm |
| May | 11.8 °C | 23.8 °C | 123.19 mm |
| June | 16.4 °C | 28.5 °C | 115.06 mm |
| July | 18.8 °C | 30.3 °C | 100.33 mm |
| August | 18.2 °C | 30.1 °C | 83.31 mm |
| September | 13.7 °C | 26.7 °C | 84.07 mm |
| October | 6.7 °C | 19.8 °C | 84.33 mm |
| November | 1.3 °C | 12.6 °C | 87.38 mm |
| December | -2.2 °C | 6.7 °C | 92.2 mm |
| Annual | 6.9 °C | 18.4 °C | 1147.82 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |