Macomb, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41 °F (low) to 61.5 °F (high). Annual precipitation averages 39 Inches. Macomb is located in USDA Plant Hardiness Zone 6a. 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 | 15.6 °F | 32.6 °F | 1.82 in. |
| February | 19.2 °F | 37.3 °F | 1.9 in. |
| March | 29.3 °F | 49.7 °F | 2.3 in. |
| April | 39.9 °F | 62.8 °F | 3.92 in. |
| May | 52.0 °F | 73.3 °F | 5.15 in. |
| June | 61.6 °F | 82.0 °F | 4.93 in. |
| July | 64.6 °F | 84.9 °F | 4.02 in. |
| August | 62.1 °F | 83.3 °F | 3.5 in. |
| September | 53.7 °F | 78.0 °F | 3.76 in. |
| October | 42.2 °F | 65.6 °F | 3.13 in. |
| November | 31.0 °F | 50.5 °F | 2.68 in. |
| December | 21.3 °F | 37.8 °F | 1.91 in. |
| Annual | 41 °F | 61.5 °F | 39.02 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |