| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F | |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F | |
| 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: | 47b - Des Moines Lobe | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 50514 - Armstrong, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 4 | 11 | 23 | 35 | 48 | 58 | 61 | 59 | 49 | 37 | 24 | 10 | 35 |
| Avg Max Temp (°F) | 23 | 29 | 41 | 57 | 71 | 80 | 83 | 80 | 73 | 60 | 41 | 27 | 55 |
| Avg Precip (In.) | .76 | .67 | 1.89 | 3.07 | 3.8 | 4.52 | 4.04 | 4.14 | 2.76 | 2.21 | 1.79 | .85 | 30.5 |