| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| 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: | 25d - Flat to Rolling Plains |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 80020 - Broomfield, CO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 17 | 20 | 26 | 34 | 43 | 52 | 57 | 56 | 46 | 36 | 25 | 18 | 36 |
| Avg Max Temp (°F) | 44 | 48 | 54 | 62 | 71 | 82 | 88 | 86 | 77 | 66 | 52 | 45 | 64 |
| Avg Precip (In.) | .4 | .36 | 1 | 1.92 | 2.3 | 1.61 | 1.62 | 1.39 | 1 | .84 | .84 | .47 | 13.75 |