| 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 5a: -20F to -15F | |
| Average First Frost Date: | Oct. 1 - Oct. 10 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate | |
| Ecoregion: | 25d - Flat to Rolling Plains | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 80504 - Longmont, CO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 12 | 17 | 24 | 32 | 42 | 51 | 56 | 54 | 44 | 33 | 22 | 14 | 33 |
| Avg Max Temp (°F) | 42 | 48 | 55 | 63 | 73 | 84 | 89 | 87 | 78 | 67 | 51 | 44 | 65 |
| Avg Precip (In.) | .38 | .38 | 1.15 | 1.81 | 2.36 | 1.48 | 1.35 | 1.36 | 1.18 | .82 | .79 | .45 | 13.51 |