Orion, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.4 °F (low) to 59.8 °F (high). Annual precipitation averages 38.4 Inches. Orion 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 | 14.0 °F | 30.1 °F | 1.62 in. |
| February | 17.5 °F | 34.6 °F | 1.82 in. |
| March | 28.0 °F | 47.8 °F | 2.43 in. |
| April | 39.0 °F | 61.1 °F | 3.74 in. |
| May | 51.0 °F | 72.1 °F | 4.92 in. |
| June | 60.9 °F | 81.0 °F | 4.84 in. |
| July | 64.6 °F | 84.1 °F | 4.16 in. |
| August | 62.4 °F | 82.3 °F | 3.87 in. |
| September | 54.1 °F | 76.5 °F | 3.66 in. |
| October | 42.3 °F | 63.6 °F | 2.9 in. |
| November | 30.4 °F | 48.5 °F | 2.33 in. |
| December | 20.0 °F | 35.6 °F | 2.06 in. |
| Annual | 40.4 °F | 59.8 °F | 38.35 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 |