Aitkin, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30.4 °F (low) to 51.2 °F (high). Annual precipitation averages 29.7 Inches. Aitkin 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 | -0.4 °F | 19.2 °F | 0.84 in. |
| February | 2.7 °F | 25.0 °F | 0.75 in. |
| March | 15.7 °F | 37.6 °F | 1.45 in. |
| April | 29.6 °F | 51.7 °F | 2.43 in. |
| May | 42.1 °F | 65.1 °F | 3.58 in. |
| June | 52.6 °F | 74.6 °F | 4.46 in. |
| July | 57.0 °F | 79.2 °F | 4.47 in. |
| August | 54.2 °F | 76.9 °F | 3.49 in. |
| September | 45.9 °F | 68.7 °F | 2.96 in. |
| October | 34.3 °F | 54.3 °F | 2.72 in. |
| November | 22.0 °F | 37.9 °F | 1.51 in. |
| December | 8.7 °F | 24.7 °F | 1.0 in. |
| Annual | 30.4 °F | 51.2 °F | 29.66 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 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |