Rome, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.4 °F (low) to 62 °F (high). Annual precipitation averages 37.6 Inches. Rome 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 | 16.3 °F | 32.7 °F | 2.06 in. |
| February | 19.7 °F | 37.2 °F | 1.89 in. |
| March | 29.6 °F | 49.7 °F | 2.51 in. |
| April | 40.2 °F | 63.2 °F | 3.76 in. |
| May | 51.5 °F | 74.0 °F | 4.94 in. |
| June | 61.1 °F | 82.9 °F | 4.12 in. |
| July | 64.8 °F | 85.9 °F | 3.58 in. |
| August | 62.7 °F | 84.5 °F | 3.66 in. |
| September | 54.5 °F | 78.8 °F | 3.44 in. |
| October | 42.9 °F | 66.1 °F | 2.93 in. |
| November | 31.8 °F | 50.8 °F | 2.6 in. |
| December | 22.2 °F | 38.0 °F | 2.06 in. |
| Annual | 41.4 °F | 62 °F | 37.55 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 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 |