Groton, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.3 °F (low) to 54.6 °F (high). Annual precipitation averages 23 Inches. Groton is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.9 °F | 21.4 °F | 0.6 in. |
| February | 6.6 °F | 26.9 °F | 0.64 in. |
| March | 19.0 °F | 39.7 °F | 1.0 in. |
| April | 31.7 °F | 55.6 °F | 2.07 in. |
| May | 44.8 °F | 68.4 °F | 3.11 in. |
| June | 55.6 °F | 78.0 °F | 3.93 in. |
| July | 60.0 °F | 82.9 °F | 3.62 in. |
| August | 57.2 °F | 81.7 °F | 2.25 in. |
| September | 47.8 °F | 73.6 °F | 2.13 in. |
| October | 34.2 °F | 58.5 °F | 2.21 in. |
| November | 20.4 °F | 41.1 °F | 0.77 in. |
| December | 8.5 °F | 27.0 °F | 0.65 in. |
| Annual | 32.3 °F | 54.6 °F | 22.98 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |