Knife River, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.4 °F (low) to 48.5 °F (high). Annual precipitation averages 31.7 Inches. Knife River 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.5 °F | 22.6 °F | 0.96 in. |
| February | 7.7 °F | 26.6 °F | 1.1 in. |
| March | 18.8 °F | 35.3 °F | 1.36 in. |
| April | 30.7 °F | 46.1 °F | 2.47 in. |
| May | 39.2 °F | 56.8 °F | 3.53 in. |
| June | 46.8 °F | 64.3 °F | 4.73 in. |
| July | 56.2 °F | 72.9 °F | 4.01 in. |
| August | 57.1 °F | 72.5 °F | 3.53 in. |
| September | 49.5 °F | 65.0 °F | 3.47 in. |
| October | 38.7 °F | 52.4 °F | 3.11 in. |
| November | 25.8 °F | 39.4 °F | 1.97 in. |
| December | 13.2 °F | 27.7 °F | 1.48 in. |
| Annual | 32.4 °F | 48.5 °F | 31.72 in. |
| 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 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |