Walnut Grove, Minnesota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 1.6 °C (low) to 12.7 °C (high). Annual precipitation averages 754.6 Millimeters. Walnut Grove is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.7 °C | -4.9 °C | 19.56 mm |
| February | -12.4 °C | -2.4 °C | 19.81 mm |
| March | -5.8 °C | 4.2 °C | 41.15 mm |
| April | 0.9 °C | 12.9 °C | 75.44 mm |
| May | 8.3 °C | 20.3 °C | 102.11 mm |
| June | 14.5 °C | 26 °C | 116.33 mm |
| July | 16.4 °C | 27.9 °C | 91.19 mm |
| August | 14.8 °C | 26.7 °C | 88.39 mm |
| September | 10 °C | 23.1 °C | 83.82 mm |
| October | 2.7 °C | 15.2 °C | 59.18 mm |
| November | -4.4 °C | 5.6 °C | 33.78 mm |
| December | -11 °C | -2 °C | 23.88 mm |
| Annual | 1.6 °C | 12.7 °C | 754.64 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |