| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F | |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F | |
| Average First Frost Date: | Oct. 1 - Oct. 10 | |
| Average Last Frost Date: | May 11 - May 20 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 47c - Iowan Surface | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 50616 - Charles City, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 6 | 12 | 24 | 36 | 48 | 57 | 61 | 59 | 50 | 38 | 25 | 12 | 36 |
| Avg Max Temp (°F) | 24 | 31 | 43 | 59 | 71 | 81 | 83 | 81 | 74 | 62 | 43 | 28 | 57 |
| Avg Precip (In.) | .94 | .87 | 2.03 | 3.44 | 4.11 | 5.07 | 4.5 | 4.55 | 3.36 | 2.46 | 2.14 | 1.1 | 34.57 |