Siloam, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.6 °C (low) to 23.3 °C (high). Annual precipitation averages 1187.7 Millimeters. Siloam is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.7 °C | 12.8 °C | 102.11 mm |
| February | 2.1 °C | 14.8 °C | 111.76 mm |
| March | 5.4 °C | 19.1 °C | 118.36 mm |
| April | 9.6 °C | 23.7 °C | 88.65 mm |
| May | 14.5 °C | 27.5 °C | 81.79 mm |
| June | 19 °C | 31.2 °C | 106.93 mm |
| July | 20.9 °C | 32.8 °C | 106.93 mm |
| August | 20.4 °C | 32 °C | 107.19 mm |
| September | 17.1 °C | 29.2 °C | 99.57 mm |
| October | 10.8 °C | 24.2 °C | 68.07 mm |
| November | 4.8 °C | 18.4 °C | 83.31 mm |
| December | 1.9 °C | 13.9 °C | 113.03 mm |
| Annual | 10.6 °C | 23.3 °C | 1187.7 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |