Fallis, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.2 °C (low) to 22.1 °C (high). Annual precipitation averages 928.9 Millimeters. Fallis is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.2 °C | 9.6 °C | 33.53 mm |
| February | -1.4 °C | 11.8 °C | 39.88 mm |
| March | 3.4 °C | 17 °C | 68.58 mm |
| April | 8.4 °C | 22.1 °C | 96.52 mm |
| May | 14.2 °C | 26.3 °C | 127.76 mm |
| June | 19.4 °C | 30.9 °C | 122.17 mm |
| July | 21.7 °C | 34.1 °C | 84.84 mm |
| August | 20.9 °C | 33.9 °C | 82.8 mm |
| September | 16.3 °C | 29.6 °C | 88.65 mm |
| October | 9.5 °C | 23.3 °C | 87.12 mm |
| November | 3.3 °C | 16.5 °C | 52.32 mm |
| December | -1.8 °C | 10.4 °C | 44.7 mm |
| Annual | 9.2 °C | 22.1 °C | 928.87 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |