Putnam, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.5 °C (low) to 21.7 °C (high). Annual precipitation averages 719.1 Millimeters. Putnam is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.8 °C | 9.2 °C | 20.32 mm |
| February | -3.3 °C | 10.8 °C | 27.94 mm |
| March | 1.5 °C | 16.3 °C | 53.59 mm |
| April | 6.2 °C | 21.1 °C | 73.91 mm |
| May | 12.2 °C | 26.3 °C | 98.55 mm |
| June | 18 °C | 31.3 °C | 97.03 mm |
| July | 20.3 °C | 34.6 °C | 58.42 mm |
| August | 19.3 °C | 34 °C | 82.04 mm |
| September | 15.3 °C | 29.6 °C | 68.33 mm |
| October | 8 °C | 22.4 °C | 68.33 mm |
| November | 1.4 °C | 15.7 °C | 37.85 mm |
| December | -3.7 °C | 9.3 °C | 32.77 mm |
| Annual | 7.5 °C | 21.7 °C | 719.08 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |