Farmington, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.8 °F (low) to 62.6 °F (high). Annual precipitation averages 38.6 Inches. Farmington is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.9 °F | 33.5 °F | 1.5 in. |
| February | 20.4 °F | 38.1 °F | 1.8 in. |
| March | 30.8 °F | 50.8 °F | 2.4 in. |
| April | 41.7 °F | 64.2 °F | 3.75 in. |
| May | 53.2 °F | 74.4 °F | 5.29 in. |
| June | 62.9 °F | 83.6 °F | 4.94 in. |
| July | 66.8 °F | 87.4 °F | 4.21 in. |
| August | 64.6 °F | 85.9 °F | 3.8 in. |
| September | 56.1 °F | 78.6 °F | 3.73 in. |
| October | 44.5 °F | 65.4 °F | 3.06 in. |
| November | 32.8 °F | 50.9 °F | 2.35 in. |
| December | 22.7 °F | 38.5 °F | 1.81 in. |
| Annual | 42.8 °F | 62.6 °F | 38.64 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |