Henry, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.8 °F (low) to 53.1 °F (high). Annual precipitation averages 24.3 Inches. Henry 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 | 3.1 °F | 21.3 °F | 0.59 in. |
| February | 6.8 °F | 26.1 °F | 0.64 in. |
| March | 18.8 °F | 38.3 °F | 1.05 in. |
| April | 31.5 °F | 53.5 °F | 2.28 in. |
| May | 44.5 °F | 66.2 °F | 3.17 in. |
| June | 55.4 °F | 76.1 °F | 4.03 in. |
| July | 60.1 °F | 81.3 °F | 3.48 in. |
| August | 57.7 °F | 79.5 °F | 2.75 in. |
| September | 48.9 °F | 71.6 °F | 2.59 in. |
| October | 35.0 °F | 56.5 °F | 2.23 in. |
| November | 21.5 °F | 40.4 °F | 0.81 in. |
| December | 9.9 °F | 26.7 °F | 0.67 in. |
| Annual | 32.8 °F | 53.1 °F | 24.29 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 |