Ottertail, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.6 °F (low) to 51.3 °F (high). Annual precipitation averages 27 Inches. Ottertail 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.2 °F | 18.2 °F | 0.66 in. |
| February | 2.9 °F | 23.2 °F | 0.62 in. |
| March | 16.5 °F | 36.3 °F | 1.16 in. |
| April | 30.6 °F | 52.4 °F | 2.15 in. |
| May | 44.0 °F | 65.8 °F | 3.46 in. |
| June | 55.0 °F | 75.2 °F | 4.56 in. |
| July | 59.6 °F | 79.7 °F | 4.17 in. |
| August | 56.9 °F | 78.0 °F | 3.01 in. |
| September | 48.7 °F | 70.1 °F | 2.8 in. |
| October | 35.5 °F | 54.8 °F | 2.69 in. |
| November | 21.5 °F | 37.5 °F | 0.95 in. |
| December | 7.8 °F | 24.0 °F | 0.77 in. |
| Annual | 31.6 °F | 51.3 °F | 27 in. |
| 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 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |