| 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: | 47f - Rolling Loess Prairies | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 50138 - Knoxville, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 11 | 16 | 27 | 38 | 50 | 60 | 65 | 62 | 53 | 41 | 28 | 16 | 39 |
| Avg Max Temp (°F) | 29 | 36 | 48 | 61 | 72 | 81 | 86 | 84 | 76 | 64 | 47 | 34 | 60 |
| Avg Precip (In.) | .9 | 1.15 | 2.08 | 3.79 | 4.48 | 4.42 | 4.4 | 4.14 | 3.68 | 2.73 | 2.32 | 1.2 | 35.28 |