Northglenn, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 2.8 °C (low) to 18.4 °C (high). Annual precipitation averages 416.6 Millimeters. Northglenn 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 | -7.1 °C | 7.7 °C | 13.46 mm |
| February | -6.3 °C | 8.3 °C | 15.75 mm |
| March | -2.2 °C | 13.2 °C | 34.54 mm |
| April | 1.3 °C | 16.4 °C | 54.36 mm |
| May | 6.4 °C | 21.3 °C | 66.55 mm |
| June | 11.6 °C | 28.2 °C | 41.15 mm |
| July | 14.9 °C | 31.6 °C | 50.55 mm |
| August | 13.8 °C | 30.3 °C | 37.85 mm |
| September | 9.2 °C | 26 °C | 35.31 mm |
| October | 2.5 °C | 18.7 °C | 29.21 mm |
| November | -2.9 °C | 12.2 °C | 22.61 mm |
| December | -7.2 °C | 7.3 °C | 15.24 mm |
| Annual | 2.8 °C | 18.4 °C | 416.58 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |