| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F |
| Average First Frost Date: | Sep. 21 - Sep. 30 |
| Average Last Frost Date: | May 21 - May 31 |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate |
| Ecoregion: | 26i - Pine-Oak Woodlands |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 80109 - Castle Rock, CO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 17 | 23 | 30 | 39 | 48 | 54 | 52 | 43 | 32 | 21 | 14 | 32 |
| Avg Max Temp (°F) | 44 | 47 | 53 | 59 | 68 | 79 | 85 | 83 | 75 | 65 | 51 | 45 | 63 |
| Avg Precip (In.) | .56 | .6 | 1.69 | 2.28 | 2.75 | 1.9 | 2.3 | 2.26 | 1.41 | 1.11 | 1.21 | .79 | 18.87 |