De Graff, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.4 °F (low) to 54 °F (high). Annual precipitation averages 27.6 Inches. De Graff 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.9 °F | 21.1 °F | 0.61 in. |
| February | 6.3 °F | 25.7 °F | 0.69 in. |
| March | 19.5 °F | 38.3 °F | 1.36 in. |
| April | 32.8 °F | 54.9 °F | 2.35 in. |
| May | 45.9 °F | 68.5 °F | 3.2 in. |
| June | 56.9 °F | 78.2 °F | 4.41 in. |
| July | 60.7 °F | 82.1 °F | 4.13 in. |
| August | 57.7 °F | 80.0 °F | 3.84 in. |
| September | 49.2 °F | 73.2 °F | 2.67 in. |
| October | 36.0 °F | 58.2 °F | 2.37 in. |
| November | 22.7 °F | 41.0 °F | 1.15 in. |
| December | 10.0 °F | 26.7 °F | 0.79 in. |
| Annual | 33.4 °F | 54 °F | 27.57 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 4b : -25°F to -20°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 |