Petersburg, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.6 °C (low) to 9.2 °C (high). Annual precipitation averages 523 Millimeters. Petersburg is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -19.4 °C | -10.1 °C | 13.97 mm |
| February | -17.4 °C | -7.2 °C | 11.18 mm |
| March | -9.9 °C | -0.3 °C | 17.27 mm |
| April | -1.8 °C | 9.6 °C | 23.11 mm |
| May | 5.7 °C | 17.9 °C | 72.39 mm |
| June | 12 °C | 23.1 °C | 99.82 mm |
| July | 14.3 °C | 25.7 °C | 90.68 mm |
| August | 12.9 °C | 25.4 °C | 69.09 mm |
| September | 7.7 °C | 20.3 °C | 53.34 mm |
| October | 0.3 °C | 11.5 °C | 39.37 mm |
| November | -7.9 °C | 1.2 °C | 18.03 mm |
| December | -15.2 °C | -6.8 °C | 14.73 mm |
| Annual | -1.6 °C | 9.2 °C | 522.98 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |