Ronneby, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.3 °C (low) to 11.7 °C (high). Annual precipitation averages 752.6 Millimeters. Ronneby is located in USDA Plant Hardiness Zone 4b. 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 | -16.7 °C | -6.2 °C | 16.76 mm |
| February | -14.7 °C | -3.2 °C | 19.3 mm |
| March | -7.6 °C | 3.8 °C | 35.81 mm |
| April | -0.3 °C | 12.1 °C | 66.55 mm |
| May | 6.9 °C | 19.6 °C | 98.3 mm |
| June | 12.7 °C | 24.8 °C | 109.22 mm |
| July | 15.2 °C | 27.2 °C | 103.12 mm |
| August | 13.7 °C | 26.1 °C | 99.57 mm |
| September | 9.1 °C | 21.8 °C | 74.42 mm |
| October | 2.1 °C | 13.7 °C | 69.6 mm |
| November | -5.2 °C | 4.3 °C | 35.31 mm |
| December | -12.2 °C | -3.2 °C | 24.64 mm |
| Annual | 0.3 °C | 11.7 °C | 752.6 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |