| 2023 Hardiness Zone: | Zone 8b: 15°F to 20°F |
| 2012 Hardiness Zone: | Zone 8a: 10°F to 15°F |
| 1990 Hardiness Zone: | Zone 7b: 5F to 10F |
| Average First Frost Date: | Nov. 11 - Nov. 20 |
| Average Last Frost Date: | Mar. 21 - Mar. 31 |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate |
| Ecoregion: | 33a - Northern Post Oak Savanna |
| Heat Zone Days: | 91 - 120 days Over 86°F |
Annual Climate Data for ZIP Code 75457 - Mount Vernon, TX | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 31 | 36 | 43 | 51 | 60 | 68 | 72 | 70 | 64 | 52 | 42 | 34 | 52 |
| Avg Max Temp (°F) | 53 | 59 | 67 | 75 | 82 | 89 | 93 | 93 | 87 | 77 | 65 | 56 | 75 |
| Avg Precip (In.) | 2.97 | 3.35 | 4.21 | 3.91 | 4.76 | 4.35 | 3.42 | 2.1 | 3.45 | 4.8 | 4.88 | 4.4 | 46.62 |