Morrison, Colorado has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2 °C (low) to 17.7 °C (high). Annual precipitation averages 501.4 Millimeters. Morrison is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.5 °C | 7.5 °C | 18.8 mm |
| February | -7.2 °C | 8.1 °C | 24.13 mm |
| March | -3.1 °C | 12.5 °C | 46.99 mm |
| April | 0.3 °C | 15.6 °C | 73.91 mm |
| May | 5.4 °C | 20.4 °C | 72.64 mm |
| June | 10.4 °C | 27.1 °C | 46.99 mm |
| July | 13.9 °C | 30.4 °C | 50.55 mm |
| August | 12.9 °C | 29.1 °C | 42.93 mm |
| September | 8.3 °C | 25 °C | 40.13 mm |
| October | 1.7 °C | 17.9 °C | 35.31 mm |
| November | -3.4 °C | 11.8 °C | 27.43 mm |
| December | -7.7 °C | 7.1 °C | 21.59 mm |
| Annual | 2 °C | 17.7 °C | 501.4 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |