| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 47c - Iowan Surface |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 52228 - Fairfax, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 16 | 27 | 38 | 50 | 59 | 63 | 61 | 52 | 40 | 28 | 15 | 38 |
| Avg Max Temp (°F) | 27 | 33 | 46 | 60 | 72 | 82 | 85 | 83 | 75 | 63 | 46 | 32 | 59 |
| Avg Precip (In.) | 1.08 | 1.12 | 2.24 | 3.32 | 4.04 | 4.59 | 4.12 | 4.38 | 3.42 | 2.32 | 2.33 | 1.49 | 34.44 |