Washta, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2 °C (low) to 14.9 °C (high). Annual precipitation averages 799.9 Millimeters. Washta is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.2 °C | -2.2 °C | 17.53 mm |
| February | -10.9 °C | 0.3 °C | 21.59 mm |
| March | -4.7 °C | 7.8 °C | 45.97 mm |
| April | 1.2 °C | 15.8 °C | 84.07 mm |
| May | 8.2 °C | 22.1 °C | 110.24 mm |
| June | 14.4 °C | 27.6 °C | 124.97 mm |
| July | 16.3 °C | 29 °C | 97.03 mm |
| August | 14.9 °C | 27.8 °C | 107.19 mm |
| September | 9.8 °C | 24.8 °C | 74.17 mm |
| October | 2.6 °C | 17.4 °C | 56.13 mm |
| November | -4.5 °C | 8.2 °C | 35.56 mm |
| December | -10.1 °C | 0.7 °C | 25.4 mm |
| Annual | 2 °C | 14.9 °C | 799.85 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |