| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | 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: | 72f - River Hills |
| Heat Zone Days: | 61 - 90 days Over 86°F |
Annual Climate Data for ZIP Code 63144 - Saint Louis, MO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 20 | 24 | 35 | 45 | 55 | 64 | 69 | 66 | 58 | 46 | 36 | 25 | 45 |
| Avg Max Temp (°F) | 38 | 44 | 55 | 66 | 76 | 85 | 89 | 87 | 80 | 69 | 54 | 42 | 66 |
| Avg Precip (In.) | 2.18 | 2.28 | 3.63 | 3.91 | 4.21 | 3.82 | 3.83 | 3.2 | 3.13 | 2.88 | 3.91 | 2.97 | 39.95 |