Gary, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.8 °F (low) to 54.2 °F (high). Annual precipitation averages 27.2 Inches. Gary 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 | 4.2 °F | 22.5 °F | 0.7 in. |
| February | 8.1 °F | 26.9 °F | 0.82 in. |
| March | 20.1 °F | 38.9 °F | 1.45 in. |
| April | 32.5 °F | 54.5 °F | 2.8 in. |
| May | 45.6 °F | 67.6 °F | 3.42 in. |
| June | 56.5 °F | 77.5 °F | 4.18 in. |
| July | 60.7 °F | 82.4 °F | 3.38 in. |
| August | 58.2 °F | 80.1 °F | 3.22 in. |
| September | 49.4 °F | 72.7 °F | 2.82 in. |
| October | 36.1 °F | 58.4 °F | 2.24 in. |
| November | 23.0 °F | 41.6 °F | 1.19 in. |
| December | 10.9 °F | 27.7 °F | 0.97 in. |
| Annual | 33.8 °F | 54.2 °F | 27.19 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |