Ottawa, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.2 °F (low) to 56.6 °F (high). Annual precipitation averages 36.9 Inches. Ottawa is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.5 °F | 27.4 °F | 1.69 in. |
| February | 14.3 °F | 31.2 °F | 1.69 in. |
| March | 24.1 °F | 43.0 °F | 2.08 in. |
| April | 35.4 °F | 56.4 °F | 3.77 in. |
| May | 46.7 °F | 68.2 °F | 4.28 in. |
| June | 56.7 °F | 78.2 °F | 4.96 in. |
| July | 61.0 °F | 82.2 °F | 3.99 in. |
| August | 59.4 °F | 80.4 °F | 3.97 in. |
| September | 51.2 °F | 73.7 °F | 3.31 in. |
| October | 39.9 °F | 60.4 °F | 2.95 in. |
| November | 28.6 °F | 45.7 °F | 2.22 in. |
| December | 18.1 °F | 32.9 °F | 1.99 in. |
| Annual | 37.2 °F | 56.6 °F | 36.9 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |