| 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: | 47a - Loess Prairies | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 51247 - Rock Valley, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 5 | 12 | 23 | 35 | 47 | 57 | 61 | 59 | 49 | 36 | 23 | 10 | 35 |
| Avg Max Temp (°F) | 25 | 32 | 44 | 60 | 72 | 82 | 85 | 83 | 75 | 62 | 42 | 29 | 58 |
| Avg Precip (In.) | .61 | .59 | 1.91 | 2.73 | 3.45 | 4.17 | 3.55 | 3.52 | 2.57 | 2 | 1.51 | .7 | 27.3 |