Patterson, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.2 °C (low) to 15.7 °C (high). Annual precipitation averages 906.5 Millimeters. Patterson is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.8 °C | -0.8 °C | 23.62 mm |
| February | -8.6 °C | 1.9 °C | 31.24 mm |
| March | -2.6 °C | 9.1 °C | 53.09 mm |
| April | 3.7 °C | 16.4 °C | 93.73 mm |
| May | 10.3 °C | 22.1 °C | 128.78 mm |
| June | 16 °C | 27.3 °C | 124.97 mm |
| July | 18.3 °C | 29.6 °C | 108.97 mm |
| August | 16.8 °C | 28.7 °C | 100.33 mm |
| September | 11.9 °C | 25.1 °C | 91.95 mm |
| October | 5.2 °C | 17.8 °C | 67.56 mm |
| November | -1.6 °C | 9.3 °C | 48.77 mm |
| December | -7.7 °C | 2.1 °C | 33.53 mm |
| Annual | 4.2 °C | 15.7 °C | 906.54 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |