| 2023 Hardiness Zone: | 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. 11 - Oct. 20 | |
| Average Last Frost Date: | Apr. 21 - Apr. 30 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 72i - Western Dissected Illinoian Till Plain | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 61462 - Monmouth, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 20 | 30 | 40 | 51 | 60 | 64 | 62 | 54 | 43 | 31 | 20 | 41 |
| Avg Max Temp (°F) | 30 | 36 | 49 | 62 | 73 | 81 | 85 | 83 | 77 | 65 | 49 | 35 | 61 |
| Avg Precip (In.) | 1.56 | 1.65 | 2.81 | 3.69 | 4.23 | 4.2 | 4.24 | 3.95 | 3.46 | 2.9 | 2.71 | 2.26 | 37.68 |