Grand Lake, Colorado has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from -5 °C (low) to 11.6 °C (high). Annual precipitation averages 460.7 Millimeters. Grand Lake 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. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.4 °C | -1.2 °C | 38.86 mm |
| February | -14.8 °C | 0.7 °C | 37.08 mm |
| March | -10.4 °C | 5.5 °C | 32.26 mm |
| April | -5.7 °C | 9.9 °C | 39.62 mm |
| May | -1.4 °C | 15.6 °C | 44.96 mm |
| June | 2.3 °C | 21.8 °C | 33.78 mm |
| July | 5.7 °C | 24.9 °C | 45.47 mm |
| August | 5 °C | 23.8 °C | 51.05 mm |
| September | 1.1 °C | 20.2 °C | 38.86 mm |
| October | -3.6 °C | 13.2 °C | 31.75 mm |
| November | -8.8 °C | 5.1 °C | 31.24 mm |
| December | -13.9 °C | -0.9 °C | 35.81 mm |
| Annual | -5 °C | 11.6 °C | 460.74 mm |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| 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 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |