Pearl City, Illinois has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.7 °F (low) to 58 °F (high). Annual precipitation averages 38.2 Inches. Pearl City is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.5 °F | 28.5 °F | 1.51 in. |
| February | 15.0 °F | 32.8 °F | 1.67 in. |
| March | 25.7 °F | 45.2 °F | 2.17 in. |
| April | 36.4 °F | 58.8 °F | 3.74 in. |
| May | 48.1 °F | 70.4 °F | 4.43 in. |
| June | 58.2 °F | 79.8 °F | 5.41 in. |
| July | 61.6 °F | 82.7 °F | 4.51 in. |
| August | 59.4 °F | 81.1 °F | 3.93 in. |
| September | 50.9 °F | 74.8 °F | 3.77 in. |
| October | 39.6 °F | 62.0 °F | 2.89 in. |
| November | 28.5 °F | 46.6 °F | 2.26 in. |
| December | 18.0 °F | 33.8 °F | 1.87 in. |
| Annual | 37.7 °F | 58 °F | 38.16 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |