Overly, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.1 °F (low) to 49.7 °F (high). Annual precipitation averages 18.6 Inches. Overly is located in USDA Plant Hardiness Zone 3b. 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 | -4.2 °F | 15.5 °F | 0.52 in. |
| February | -0.7 °F | 20.4 °F | 0.52 in. |
| March | 12.6 °F | 32.9 °F | 0.77 in. |
| April | 27.4 °F | 51.4 °F | 0.93 in. |
| May | 40.2 °F | 65.4 °F | 2.39 in. |
| June | 51.2 °F | 74.1 °F | 3.58 in. |
| July | 55.4 °F | 79.3 °F | 3.09 in. |
| August | 52.6 °F | 79.4 °F | 2.47 in. |
| September | 42.8 °F | 69.5 °F | 1.6 in. |
| October | 29.7 °F | 53.1 °F | 1.33 in. |
| November | 15.2 °F | 34.6 °F | 0.76 in. |
| December | 2.4 °F | 20.7 °F | 0.66 in. |
| Annual | 27.1 °F | 49.7 °F | 18.62 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 3b : -35°F to -30°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 |