Monticello, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.4 °C (low) to 23.5 °C (high). Annual precipitation averages 1201.7 Millimeters. Monticello is located in USDA Plant Hardiness Zone 8b. 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 | 0.5 °C | 13.3 °C | 105.66 mm |
| February | 2.1 °C | 15.4 °C | 111 mm |
| March | 5.1 °C | 19.6 °C | 124.21 mm |
| April | 9.2 °C | 23.8 °C | 96.01 mm |
| May | 14.3 °C | 27.8 °C | 67.06 mm |
| June | 18.9 °C | 31 °C | 112.01 mm |
| July | 20.9 °C | 32.7 °C | 112.78 mm |
| August | 20.4 °C | 31.9 °C | 105.66 mm |
| September | 17.1 °C | 29.2 °C | 92.46 mm |
| October | 10.6 °C | 24.1 °C | 71.12 mm |
| November | 4.5 °C | 18.8 °C | 90.42 mm |
| December | 1.6 °C | 14.4 °C | 113.28 mm |
| Annual | 10.4 °C | 23.5 °C | 1201.67 mm |
| 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 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 |