| 2023 Hardiness Zone: | Zone 5b: -15°F to -10°F | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F 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: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 54f - Valparaiso-Wheaton Morainal Complex | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 60152 - Marengo, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 15 | 26 | 36 | 47 | 57 | 62 | 60 | 51 | 39 | 28 | 17 | 37 |
| Avg Max Temp (°F) | 28 | 33 | 45 | 59 | 71 | 81 | 85 | 82 | 75 | 63 | 46 | 33 | 58 |
| Avg Precip (In.) | 1.51 | 1.3 | 2.38 | 3.69 | 3.98 | 4.54 | 3.9 | 4.46 | 3.38 | 2.63 | 2.74 | 1.99 | 36.5 |