Morrison, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.3 °F (low) to 59.3 °F (high). Annual precipitation averages 38.8 Inches. Morrison 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.9 °F | 29.6 °F | 1.67 in. |
| February | 16.6 °F | 34.1 °F | 1.77 in. |
| March | 27.3 °F | 46.7 °F | 2.5 in. |
| April | 38.1 °F | 60.3 °F | 3.78 in. |
| May | 49.9 °F | 71.7 °F | 4.84 in. |
| June | 59.8 °F | 80.9 °F | 5.13 in. |
| July | 63.2 °F | 83.9 °F | 4.16 in. |
| August | 61.0 °F | 82.3 °F | 4.08 in. |
| September | 52.6 °F | 76.2 °F | 3.67 in. |
| October | 41.0 °F | 63.2 °F | 2.8 in. |
| November | 29.6 °F | 48.0 °F | 2.33 in. |
| December | 19.3 °F | 35.1 °F | 2.05 in. |
| Annual | 39.3 °F | 59.3 °F | 38.78 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |