Rockport, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.6 °F (low) to 63.9 °F (high). Annual precipitation averages 38.6 Inches. Rockport is located in USDA Plant Hardiness Zone 6a. 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 | 19.3 °F | 36.3 °F | 2.01 in. |
| February | 22.7 °F | 41.4 °F | 1.87 in. |
| March | 32.0 °F | 52.5 °F | 2.75 in. |
| April | 42.7 °F | 65.0 °F | 4.0 in. |
| May | 53.7 °F | 74.6 °F | 4.68 in. |
| June | 63.0 °F | 83.4 °F | 4.58 in. |
| July | 66.6 °F | 87.0 °F | 3.9 in. |
| August | 64.5 °F | 85.9 °F | 3.38 in. |
| September | 55.9 °F | 79.6 °F | 3.53 in. |
| October | 44.6 °F | 67.2 °F | 2.9 in. |
| November | 33.8 °F | 53.2 °F | 2.81 in. |
| December | 24.4 °F | 40.9 °F | 2.15 in. |
| Annual | 43.6 °F | 63.9 °F | 38.56 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 6a : -10°F to -5°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 |