Olivet, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.2 °F (low) to 62.3 °F (high). Annual precipitation averages 41.4 Inches. Olivet is located in USDA Plant Hardiness Zone 6a. 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 | 18.2 °F | 34.2 °F | 2.56 in. |
| February | 21.4 °F | 38.7 °F | 2.2 in. |
| March | 30.7 °F | 50.4 °F | 2.96 in. |
| April | 41.3 °F | 63.6 °F | 4.3 in. |
| May | 52.6 °F | 74.2 °F | 4.58 in. |
| June | 61.8 °F | 82.4 °F | 4.87 in. |
| July | 64.3 °F | 84.8 °F | 4.24 in. |
| August | 62.1 °F | 83.5 °F | 3.19 in. |
| September | 54.4 °F | 78.7 °F | 3.04 in. |
| October | 43.1 °F | 66.4 °F | 3.44 in. |
| November | 32.6 °F | 51.4 °F | 3.38 in. |
| December | 23.9 °F | 39.1 °F | 2.59 in. |
| Annual | 42.2 °F | 62.3 °F | 41.35 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |