Trenton, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 46.1 °F (low) to 65.9 °F (high). Annual precipitation averages 42.7 Inches. Trenton 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 | 22.7 °F | 39.4 °F | 2.76 in. |
| February | 26.1 °F | 44.6 °F | 2.33 in. |
| March | 34.8 °F | 55.0 °F | 3.3 in. |
| April | 45.4 °F | 66.9 °F | 4.82 in. |
| May | 56.3 °F | 76.0 °F | 4.92 in. |
| June | 65.1 °F | 85.0 °F | 4.75 in. |
| July | 68.8 °F | 88.2 °F | 3.9 in. |
| August | 66.6 °F | 87.2 °F | 3.19 in. |
| September | 58.2 °F | 80.8 °F | 3.23 in. |
| October | 46.6 °F | 69.2 °F | 3.07 in. |
| November | 35.6 °F | 54.9 °F | 3.71 in. |
| December | 27.2 °F | 43.8 °F | 2.75 in. |
| Annual | 46.1 °F | 65.9 °F | 42.73 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |