| 2023 Hardiness Zone: | Zone 6b: -5°F to 0°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | Apr. 11 - Apr. 20 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 72f - River Hills |
| Heat Zone Days: | 61 - 90 days Over 86°F |
Annual Climate Data for ZIP Code 63357 - Marthasville, MO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 20 | 24 | 34 | 44 | 53 | 62 | 67 | 65 | 56 | 45 | 35 | 24 | 44 |
| Avg Max Temp (°F) | 39 | 45 | 56 | 68 | 77 | 85 | 90 | 88 | 81 | 70 | 55 | 43 | 66 |
| Avg Precip (In.) | 2.06 | 2.19 | 3.52 | 3.89 | 4.4 | 3.84 | 3.82 | 3.23 | 3.34 | 3.02 | 3.85 | 2.79 | 39.94 |