Stanley, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.9 °F (low) to 49.9 °F (high). Annual precipitation averages 18.5 Inches. Stanley 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 | -0.4 °F | 17.7 °F | 0.54 in. |
| February | 3.4 °F | 22.1 °F | 0.51 in. |
| March | 14.8 °F | 34.3 °F | 0.71 in. |
| April | 27.3 °F | 51.4 °F | 1.1 in. |
| May | 39.2 °F | 63.7 °F | 2.52 in. |
| June | 49.9 °F | 72.0 °F | 3.93 in. |
| July | 54.2 °F | 78.4 °F | 2.92 in. |
| August | 52.0 °F | 79.2 °F | 1.96 in. |
| September | 42.2 °F | 69.4 °F | 1.58 in. |
| October | 30.2 °F | 52.9 °F | 1.36 in. |
| November | 16.9 °F | 35.5 °F | 0.74 in. |
| December | 5.4 °F | 22.1 °F | 0.65 in. |
| Annual | 27.9 °F | 49.9 °F | 18.52 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |