Brighton, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 1.7 °C (low) to 18.4 °C (high). Annual precipitation averages 344.2 Millimeters. Brighton is located in USDA Plant Hardiness Zone 5b. 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 | -9.3 °C | 6.7 °C | 9.65 mm |
| February | -8.1 °C | 7.4 °C | 10.92 mm |
| March | -3.3 °C | 13.6 °C | 27.18 mm |
| April | 0.6 °C | 16.9 °C | 44.7 mm |
| May | 6 °C | 21.8 °C | 60.2 mm |
| June | 11.2 °C | 28.7 °C | 34.8 mm |
| July | 14.4 °C | 32.1 °C | 37.34 mm |
| August | 13.1 °C | 30.8 °C | 39.12 mm |
| September | 8.2 °C | 26.5 °C | 29.21 mm |
| October | 1.2 °C | 18.8 °C | 24.64 mm |
| November | -4.6 °C | 11.7 °C | 17.27 mm |
| December | -9.4 °C | 6.2 °C | 9.14 mm |
| Annual | 1.7 °C | 18.4 °C | 344.17 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |