Lyons, Colorado has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.1 °C (low) to 17.9 °C (high). Annual precipitation averages 442.2 Millimeters. Lyons is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.7 °C | 7.1 °C | 13.97 mm |
| February | -6.9 °C | 7.6 °C | 15.75 mm |
| March | -2.8 °C | 12.7 °C | 34.8 mm |
| April | 0.6 °C | 16.2 °C | 52.58 mm |
| May | 5.6 °C | 20.9 °C | 81.03 mm |
| June | 10.6 °C | 27.7 °C | 56.39 mm |
| July | 14 °C | 31.1 °C | 41.15 mm |
| August | 12.8 °C | 29.8 °C | 41.15 mm |
| September | 8.4 °C | 25.6 °C | 45.47 mm |
| October | 2.1 °C | 18.3 °C | 28.96 mm |
| November | -3.3 °C | 11.5 °C | 19.3 mm |
| December | -7.7 °C | 6.7 °C | 11.68 mm |
| Annual | 2.1 °C | 17.9 °C | 442.23 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |