| 2023 Hardiness Zone: | Zone 5b: -15°F to -10°F | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F | |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 54g - Rock River Hills | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 61054 - Mount Morris, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 9 | 15 | 26 | 37 | 48 | 57 | 62 | 59 | 50 | 39 | 28 | 16 | 37 |
| Avg Max Temp (°F) | 26 | 32 | 44 | 58 | 70 | 79 | 82 | 80 | 74 | 62 | 45 | 32 | 57 |
| Avg Precip (In.) | 1.43 | 1.35 | 2.42 | 3.54 | 4.09 | 4.62 | 3.74 | 4.31 | 3.4 | 2.66 | 2.74 | 1.98 | 36.28 |