Alma, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45 °F (low) to 64.7 °F (high). Annual precipitation averages 44.9 Inches. Alma 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 | 22.1 °F | 37.9 °F | 3.03 in. |
| February | 25.5 °F | 42.8 °F | 2.47 in. |
| March | 33.9 °F | 53.3 °F | 3.66 in. |
| April | 44.2 °F | 65.4 °F | 4.62 in. |
| May | 55.2 °F | 75.1 °F | 4.94 in. |
| June | 64.1 °F | 84.0 °F | 4.8 in. |
| July | 67.3 °F | 86.9 °F | 4.18 in. |
| August | 64.5 °F | 85.9 °F | 3.62 in. |
| September | 56.2 °F | 80.0 °F | 3.44 in. |
| October | 45.1 °F | 68.6 °F | 3.4 in. |
| November | 35.1 °F | 53.7 °F | 3.84 in. |
| December | 27.1 °F | 42.3 °F | 2.91 in. |
| Annual | 45 °F | 64.7 °F | 44.91 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 |