Denham, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30 °F (low) to 50.9 °F (high). Annual precipitation averages 31 Inches. Denham is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.1 °F | 19.5 °F | 0.8 in. |
| February | 3.5 °F | 25.1 °F | 0.82 in. |
| March | 15.9 °F | 37.3 °F | 1.43 in. |
| April | 28.9 °F | 50.8 °F | 2.45 in. |
| May | 40.3 °F | 64.5 °F | 3.45 in. |
| June | 49.9 °F | 73.7 °F | 4.59 in. |
| July | 55.6 °F | 78.7 °F | 4.52 in. |
| August | 54.0 °F | 76.7 °F | 3.92 in. |
| September | 46.2 °F | 68.4 °F | 3.22 in. |
| October | 34.7 °F | 53.8 °F | 3.02 in. |
| November | 22.1 °F | 37.8 °F | 1.58 in. |
| December | 8.6 °F | 24.5 °F | 1.15 in. |
| Annual | 30 °F | 50.9 °F | 30.95 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |