McCoy, Colorado has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2.8 °C (low) to 15.1 °C (high). Annual precipitation averages 350 Millimeters. McCoy is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.4 °C | 0.2 °C | 21.59 mm |
| February | -11.7 °C | 2.9 °C | 19.81 mm |
| March | -6.6 °C | 8.6 °C | 19.05 mm |
| April | -2.7 °C | 14.7 °C | 36.07 mm |
| May | 1.2 °C | 20.3 °C | 39.62 mm |
| June | 4.9 °C | 26.6 °C | 30.73 mm |
| July | 8.6 °C | 29.8 °C | 33.78 mm |
| August | 7.4 °C | 28.5 °C | 35.56 mm |
| September | 3.1 °C | 24.6 °C | 36.58 mm |
| October | -2.4 °C | 16.8 °C | 28.19 mm |
| November | -7.9 °C | 7.5 °C | 24.38 mm |
| December | -13.3 °C | 0.3 °C | 24.64 mm |
| Annual | -2.8 °C | 15.1 °C | 350 mm |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Exceptional Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |