Simla, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 0.2 °C (low) to 17 °C (high). Annual precipitation averages 434.6 Millimeters. Simla is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.4 °C | 6.1 °C | 8.38 mm |
| February | -9.3 °C | 6.7 °C | 10.92 mm |
| March | -5.2 °C | 11.7 °C | 27.18 mm |
| April | -1.4 °C | 15.3 °C | 47.24 mm |
| May | 4.1 °C | 20.3 °C | 61.21 mm |
| June | 9.3 °C | 26.8 °C | 56.39 mm |
| July | 12.7 °C | 29.9 °C | 66.29 mm |
| August | 11.8 °C | 28.4 °C | 75.44 mm |
| September | 6.9 °C | 24.7 °C | 27.43 mm |
| October | 0.1 °C | 17.7 °C | 28.96 mm |
| November | -5.8 °C | 10.9 °C | 14.22 mm |
| December | -10.3 °C | 5.8 °C | 10.92 mm |
| Annual | 0.2 °C | 17 °C | 434.58 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 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 | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |