| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate |
| Ecoregion: | 25l - Front Range Fans |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 80123 - Littleton, CO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 16 | 19 | 26 | 34 | 43 | 52 | 57 | 56 | 46 | 34 | 24 | 16 | 35 |
| Avg Max Temp (°F) | 44 | 48 | 55 | 62 | 70 | 81 | 86 | 85 | 76 | 65 | 52 | 44 | 64 |
| Avg Precip (In.) | .6 | .59 | 1.43 | 2.36 | 2.72 | 1.91 | 1.81 | 1.67 | 1.39 | .97 | 1.11 | .68 | 17.24 |