Golconda, Illinois has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 47.2 °F (low) to 67 °F (high). Annual precipitation averages 49.7 Inches. Golconda is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 25.8 °F | 42.2 °F | 3.92 in. |
| February | 28.4 °F | 46.9 °F | 3.54 in. |
| March | 36.8 °F | 56.7 °F | 4.77 in. |
| April | 46.3 °F | 67.8 °F | 5.18 in. |
| May | 56.7 °F | 76.7 °F | 5.05 in. |
| June | 65.1 °F | 84.9 °F | 4.43 in. |
| July | 68.8 °F | 87.8 °F | 4.23 in. |
| August | 66.6 °F | 86.8 °F | 3.01 in. |
| September | 59.2 °F | 81.4 °F | 3.46 in. |
| October | 47.4 °F | 70.1 °F | 3.75 in. |
| November | 36.6 °F | 57.0 °F | 4.11 in. |
| December | 29.0 °F | 46.1 °F | 4.26 in. |
| Annual | 47.2 °F | 67 °F | 49.71 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |