Glennville, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.8 °C (low) to 25.6 °C (high). Annual precipitation averages 1233.9 Millimeters. Glennville is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.2 °C | 16.4 °C | 102.11 mm |
| February | 4.7 °C | 18.3 °C | 95.5 mm |
| March | 7.9 °C | 22 °C | 102.11 mm |
| April | 11.7 °C | 26.1 °C | 81.03 mm |
| May | 16.5 °C | 29.8 °C | 85.85 mm |
| June | 20.6 °C | 32.4 °C | 134.62 mm |
| July | 22.1 °C | 33.6 °C | 133.6 mm |
| August | 22 °C | 32.9 °C | 163.32 mm |
| September | 19.4 °C | 30.6 °C | 93.73 mm |
| October | 13.5 °C | 26.3 °C | 82.8 mm |
| November | 7.6 °C | 21.4 °C | 60.71 mm |
| December | 4.6 °C | 17.6 °C | 98.55 mm |
| Annual | 12.8 °C | 25.6 °C | 1233.93 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |