Ottawa, Kansas has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45 °F (low) to 66.7 °F (high). Annual precipitation averages 39.4 Inches. Ottawa 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.1 °F | 40.9 °F | 1.18 in. |
| February | 24.5 °F | 45.0 °F | 1.51 in. |
| March | 34.0 °F | 57.0 °F | 2.32 in. |
| April | 43.9 °F | 67.0 °F | 3.85 in. |
| May | 54.9 °F | 75.7 °F | 5.71 in. |
| June | 64.5 °F | 85.0 °F | 5.31 in. |
| July | 68.4 °F | 89.8 °F | 3.85 in. |
| August | 66.4 °F | 88.8 °F | 4.41 in. |
| September | 57.5 °F | 80.9 °F | 4.15 in. |
| October | 45.4 °F | 70.0 °F | 3.2 in. |
| November | 34.2 °F | 55.9 °F | 2.25 in. |
| December | 24.9 °F | 44.3 °F | 1.66 in. |
| Annual | 45 °F | 66.7 °F | 39.4 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 |