Napoleon, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.9 °F (low) to 63.6 °F (high). Annual precipitation averages 47.1 Inches. Napoleon is located in USDA Plant Hardiness Zone 6b. 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 | 21.1 °F | 37.7 °F | 3.5 in. |
| February | 23.2 °F | 42.1 °F | 3.04 in. |
| March | 31.7 °F | 52.3 °F | 3.93 in. |
| April | 42.0 °F | 64.8 °F | 4.93 in. |
| May | 52.3 °F | 74.5 °F | 5.18 in. |
| June | 61.0 °F | 81.5 °F | 4.95 in. |
| July | 64.3 °F | 84.8 °F | 4.19 in. |
| August | 62.5 °F | 84.5 °F | 3.43 in. |
| September | 54.9 °F | 78.6 °F | 3.14 in. |
| October | 43.5 °F | 66.8 °F | 3.36 in. |
| November | 32.9 °F | 53.2 °F | 3.63 in. |
| December | 25.8 °F | 42.0 °F | 3.82 in. |
| Annual | 42.9 °F | 63.6 °F | 47.1 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |