Egan, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 33.9 °F (low) to 54.5 °F (high). Annual precipitation averages 27.8 Inches. Egan 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4.8 °F | 23.2 °F | 0.57 in. |
| February | 8.6 °F | 28.0 °F | 0.77 in. |
| March | 20.6 °F | 40.4 °F | 1.38 in. |
| April | 32.8 °F | 54.8 °F | 2.73 in. |
| May | 45.8 °F | 67.3 °F | 3.72 in. |
| June | 57.1 °F | 77.3 °F | 4.45 in. |
| July | 61.1 °F | 81.9 °F | 3.53 in. |
| August | 58.2 °F | 79.4 °F | 3.45 in. |
| September | 49.1 °F | 72.6 °F | 3.09 in. |
| October | 35.5 °F | 58.6 °F | 2.18 in. |
| November | 22.2 °F | 42.1 °F | 1.06 in. |
| December | 10.7 °F | 28.1 °F | 0.87 in. |
| Annual | 33.9 °F | 54.5 °F | 27.8 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 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |