Farson, Wyoming has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 23.3 °F (low) to 55.3 °F (high). Annual precipitation averages 7.9 Inches. Farson is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.0 °F | 28.8 °F | 0.34 in. |
| February | 3.1 °F | 31.9 °F | 0.43 in. |
| March | 16.0 °F | 43.1 °F | 0.61 in. |
| April | 23.8 °F | 53.9 °F | 0.89 in. |
| May | 32.4 °F | 64.3 °F | 1.29 in. |
| June | 39.6 °F | 75.4 °F | 0.86 in. |
| July | 45.6 °F | 83.6 °F | 0.56 in. |
| August | 43.6 °F | 81.6 °F | 0.66 in. |
| September | 35.1 °F | 72.2 °F | 0.91 in. |
| October | 24.9 °F | 57.6 °F | 0.65 in. |
| November | 13.3 °F | 42.0 °F | 0.37 in. |
| December | 1.8 °F | 29.7 °F | 0.33 in. |
| Annual | 23.3 °F | 55.3 °F | 7.9 in. |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |