| 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 | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 8 - 14 days Over 86°F |
Annual Climate Data for ZIP Code 52302 - Marion, IA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 11 | 17 | 28 | 38 | 50 | 60 | 64 | 62 | 53 | 42 | 29 | 17 | 39 |
| Avg Max Temp (°F) | 28 | 34 | 47 | 61 | 73 | 82 | 85 | 83 | 75 | 64 | 46 | 32 | 59 |
| Avg Precip (In.) | 1.14 | 1.11 | 2.12 | 3.44 | 4.44 | 4.75 | 4.35 | 4.66 | 3.73 | 2.54 | 2.48 | 1.51 | 36.28 |