Florissant, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -4.6 °C (low) to 13.8 °C (high). Annual precipitation averages 361 Millimeters. Florissant is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.2 °C | 3.4 °C | 9.91 mm |
| February | -13.8 °C | 4.1 °C | 9.91 mm |
| March | -9.2 °C | 8.3 °C | 21.59 mm |
| April | -5.4 °C | 11.7 °C | 27.43 mm |
| May | -0.9 °C | 16.7 °C | 37.08 mm |
| June | 3.5 °C | 23.3 °C | 35.81 mm |
| July | 6.7 °C | 25.9 °C | 78.49 mm |
| August | 6.1 °C | 24.4 °C | 70.36 mm |
| September | 1.7 °C | 21.1 °C | 33.53 mm |
| October | -4.3 °C | 14.9 °C | 16.26 mm |
| November | -9.7 °C | 8.1 °C | 11.94 mm |
| December | -15.1 °C | 3.2 °C | 8.64 mm |
| Annual | -4.6 °C | 13.8 °C | 360.95 mm |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |