Hannibal, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44 °F (low) to 63.9 °F (high). Annual precipitation averages 39.5 Inches. Hannibal is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 19.4 °F | 36.0 °F | 1.92 in. |
| February | 22.9 °F | 41.3 °F | 2.16 in. |
| March | 32.1 °F | 52.3 °F | 2.78 in. |
| April | 43.1 °F | 64.5 °F | 4.25 in. |
| May | 53.8 °F | 74.6 °F | 4.9 in. |
| June | 63.5 °F | 83.6 °F | 4.48 in. |
| July | 67.1 °F | 87.5 °F | 3.91 in. |
| August | 65.2 °F | 86.3 °F | 3.69 in. |
| September | 56.8 °F | 79.3 °F | 3.43 in. |
| October | 45.6 °F | 66.9 °F | 3.21 in. |
| November | 34.2 °F | 53.1 °F | 2.73 in. |
| December | 24.5 °F | 41.0 °F | 2.08 in. |
| Annual | 44 °F | 63.9 °F | 39.54 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 |