Sims, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45.4 °F (low) to 65.8 °F (high). Annual precipitation averages 44.8 Inches. Sims 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.4 °F | 39.6 °F | 3.26 in. |
| February | 26.2 °F | 44.5 °F | 2.74 in. |
| March | 34.5 °F | 54.7 °F | 3.78 in. |
| April | 44.9 °F | 66.6 °F | 4.72 in. |
| May | 55.5 °F | 76.1 °F | 4.77 in. |
| June | 64.1 °F | 84.9 °F | 4.84 in. |
| July | 67.1 °F | 87.4 °F | 3.82 in. |
| August | 64.7 °F | 86.6 °F | 3.36 in. |
| September | 56.7 °F | 80.9 °F | 3.15 in. |
| October | 45.3 °F | 69.5 °F | 3.41 in. |
| November | 35.1 °F | 55.1 °F | 3.83 in. |
| December | 27.5 °F | 43.8 °F | 3.1 in. |
| Annual | 45.4 °F | 65.8 °F | 44.78 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |