| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°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 21 - May 31 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 52b - Paleozoic Plateau/Coulee Section | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 52101 - Decorah, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 6 | 13 | 24 | 36 | 47 | 57 | 61 | 59 | 50 | 39 | 26 | 13 | 36 |
| Avg Max Temp (°F) | 24 | 31 | 43 | 58 | 71 | 80 | 83 | 81 | 73 | 61 | 43 | 29 | 56 |
| Avg Precip (In.) | .93 | .84 | 1.85 | 3.67 | 3.9 | 4.6 | 4.18 | 4.59 | 3.44 | 2.33 | 2.16 | 1.1 | 33.58 |