Peru, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.8 °F (low) to 60.9 °F (high). Annual precipitation averages 36.3 Inches. Peru is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.6 °F | 31.6 °F | 1.73 in. |
| February | 19.3 °F | 36.1 °F | 1.71 in. |
| March | 28.8 °F | 48.6 °F | 2.36 in. |
| April | 39.3 °F | 62.0 °F | 3.46 in. |
| May | 50.6 °F | 73.1 °F | 4.56 in. |
| June | 60.4 °F | 82.0 °F | 4.28 in. |
| July | 64.0 °F | 84.8 °F | 3.83 in. |
| August | 62.1 °F | 83.1 °F | 3.62 in. |
| September | 54.1 °F | 77.6 °F | 3.34 in. |
| October | 42.5 °F | 65.0 °F | 2.98 in. |
| November | 31.6 °F | 49.8 °F | 2.45 in. |
| December | 21.5 °F | 36.9 °F | 1.96 in. |
| Annual | 40.8 °F | 60.9 °F | 36.28 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |