Putnam, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.4 °C (low) to 24.7 °C (high). Annual precipitation averages 1453.1 Millimeters. Putnam 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 | 1.6 °C | 14.3 °C | 141.99 mm |
| February | 3.3 °C | 16.7 °C | 134.11 mm |
| March | 6.7 °C | 21.2 °C | 147.32 mm |
| April | 10.4 °C | 25.1 °C | 117.35 mm |
| May | 15.4 °C | 29.1 °C | 104.65 mm |
| June | 19.8 °C | 32 °C | 125.98 mm |
| July | 21.4 °C | 33.3 °C | 137.92 mm |
| August | 21 °C | 33.1 °C | 121.16 mm |
| September | 17.9 °C | 30.7 °C | 94.74 mm |
| October | 11.2 °C | 25.8 °C | 85.09 mm |
| November | 5.3 °C | 19.8 °C | 108.71 mm |
| December | 2.7 °C | 15.6 °C | 134.11 mm |
| Annual | 11.4 °C | 24.7 °C | 1453.13 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |