| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | Apr. 21 - Apr. 30 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 40a - Loess Flats and Till Plains |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 63565 - Unionville, MO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 11 | 16 | 27 | 37 | 49 | 58 | 63 | 61 | 52 | 40 | 28 | 16 | 38 |
| Avg Max Temp (°F) | 31 | 38 | 50 | 62 | 72 | 82 | 86 | 85 | 77 | 65 | 49 | 36 | 61 |
| Avg Precip (In.) | 1.1 | 1.12 | 2.51 | 3.48 | 4.72 | 4.37 | 5.01 | 3.93 | 4.08 | 3.06 | 2.5 | 1.57 | 37.46 |