Fairmont, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.3 °C (low) to 21.8 °C (high). Annual precipitation averages 851.2 Millimeters. Fairmont is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.2 °C | 8.6 °C | 26.92 mm |
| February | -2.6 °C | 10.8 °C | 34.8 mm |
| March | 2.2 °C | 16.2 °C | 62.23 mm |
| April | 7 °C | 21.1 °C | 86.61 mm |
| May | 13.3 °C | 26.3 °C | 115.06 mm |
| June | 18.8 °C | 32 °C | 115.82 mm |
| July | 21.2 °C | 34.9 °C | 88.9 mm |
| August | 20.3 °C | 34.2 °C | 88.9 mm |
| September | 16 °C | 29.9 °C | 71.37 mm |
| October | 8.8 °C | 22.9 °C | 78.49 mm |
| November | 2.2 °C | 15.6 °C | 44.2 mm |
| December | -2.9 °C | 9.2 °C | 37.85 mm |
| Annual | 8.3 °C | 21.8 °C | 851.15 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |