Missouri Valley, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.1 °C (low) to 16.1 °C (high). Annual precipitation averages 834.1 Millimeters. Missouri Valley 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 | -10.9 °C | -0.3 °C | 18.8 mm |
| February | -8.8 °C | 2.3 °C | 24.13 mm |
| March | -2.7 °C | 9.6 °C | 45.97 mm |
| April | 3.4 °C | 16.8 °C | 84.58 mm |
| May | 10.3 °C | 22.7 °C | 123.19 mm |
| June | 16.3 °C | 28.2 °C | 127.51 mm |
| July | 18.4 °C | 30.1 °C | 92.71 mm |
| August | 16.9 °C | 28.9 °C | 102.62 mm |
| September | 11.7 °C | 25.5 °C | 82.8 mm |
| October | 4.6 °C | 18.3 °C | 62.99 mm |
| November | -2.4 °C | 9.5 °C | 36.32 mm |
| December | -8.1 °C | 2.1 °C | 32.51 mm |
| Annual | 4.1 °C | 16.1 °C | 834.13 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |