Rockwood, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45.9 °F (low) to 67 °F (high). Annual precipitation averages 44.9 Inches. Rockwood is located in USDA Plant Hardiness Zone 7a. 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 | 23.7 °F | 41.3 °F | 2.87 in. |
| February | 27.5 °F | 46.6 °F | 2.73 in. |
| March | 35.1 °F | 56.5 °F | 3.83 in. |
| April | 45.1 °F | 67.8 °F | 5.06 in. |
| May | 55.7 °F | 76.9 °F | 5.32 in. |
| June | 64.7 °F | 85.5 °F | 4.4 in. |
| July | 68.2 °F | 88.4 °F | 3.92 in. |
| August | 65.8 °F | 87.8 °F | 3.07 in. |
| September | 56.9 °F | 81.4 °F | 3.21 in. |
| October | 45.2 °F | 70.4 °F | 3.3 in. |
| November | 35.6 °F | 56.4 °F | 4.02 in. |
| December | 27.3 °F | 44.9 °F | 3.16 in. |
| Annual | 45.9 °F | 67 °F | 44.89 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°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 |