| 2023 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 11 - Apr. 20 |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate |
| Ecoregion: | 39i - Eastern Ozark Border |
| Heat Zone Days: | 61 - 90 days Over 86°F |
Annual Climate Data for ZIP Code 63048 - Herculaneum, MO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 18 | 22 | 31 | 41 | 50 | 59 | 65 | 63 | 54 | 42 | 32 | 23 | 42 |
| Avg Max Temp (°F) | 39 | 46 | 57 | 67 | 76 | 84 | 89 | 87 | 80 | 70 | 55 | 43 | 66 |
| Avg Precip (In.) | 2.22 | 2.36 | 3.81 | 4.08 | 4.06 | 3.84 | 3.08 | 3.49 | 3.11 | 2.81 | 4.1 | 3.16 | 40.12 |