Osceola, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.9 °F (low) to 60.4 °F (high). Annual precipitation averages 37.7 Inches. Osceola 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.3 °F | 31.3 °F | 0.93 in. |
| February | 17.2 °F | 36.0 °F | 1.28 in. |
| March | 27.8 °F | 48.8 °F | 2.23 in. |
| April | 38.8 °F | 61.4 °F | 3.97 in. |
| May | 50.6 °F | 71.4 °F | 5.5 in. |
| June | 60.9 °F | 81.0 °F | 4.94 in. |
| July | 65.1 °F | 85.2 °F | 4.26 in. |
| August | 62.4 °F | 83.5 °F | 4.32 in. |
| September | 53.2 °F | 76.2 °F | 3.84 in. |
| October | 41.3 °F | 64.1 °F | 2.73 in. |
| November | 29.2 °F | 49.0 °F | 2.14 in. |
| December | 18.8 °F | 36.3 °F | 1.51 in. |
| Annual | 39.9 °F | 60.4 °F | 37.65 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |