Glenn, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 50.1 °F (low) to 74.1 °F (high). Annual precipitation averages 54.4 Inches. Glenn is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 32.2 °F | 55.2 °F | 5.32 in. |
| February | 35.2 °F | 59.3 °F | 5.24 in. |
| March | 41.2 °F | 67.1 °F | 5.2 in. |
| April | 47.8 °F | 75.0 °F | 4.55 in. |
| May | 57.0 °F | 82.0 °F | 3.87 in. |
| June | 64.9 °F | 87.6 °F | 4.6 in. |
| July | 68.5 °F | 90.5 °F | 4.99 in. |
| August | 67.8 °F | 89.3 °F | 4.19 in. |
| September | 61.7 °F | 84.7 °F | 3.7 in. |
| October | 50.1 °F | 75.6 °F | 3.23 in. |
| November | 39.8 °F | 65.5 °F | 4.19 in. |
| December | 34.9 °F | 57.5 °F | 5.27 in. |
| Annual | 50.1 °F | 74.1 °F | 54.35 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |