| 2023 Hardiness Zone: | Zone 10a: 30°F to 35°F | |
| 2012 Hardiness Zone: | Zone 9b: 25°F to 30°F | |
| 1990 Hardiness Zone: | Zone 9b: 25F to 30F | |
| Average First Frost Date: | Jan. 11 - Jan. 20 | |
| Average Last Frost Date: | Jan. 21 - Jan. 31 | |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate | |
| Ecoregion: | 34f - Lower Rio Grande Alluvial Floodplain | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 181 - 210 days Over 86°F |
Annual Climate Data for ZIP Code 78570 - Mercedes, TX | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 48 | 51 | 58 | 63 | 70 | 73 | 74 | 74 | 71 | 64 | 56 | 49 | 62 |
| Avg Max Temp (°F) | 69 | 73 | 80 | 85 | 89 | 93 | 96 | 96 | 92 | 86 | 78 | 71 | 84 |
| Avg Precip (In.) | 1.31 | 1.49 | 1.04 | 1.49 | 2.75 | 2.91 | 2.09 | 2.49 | 4.54 | 2.59 | 1.38 | 1.18 | 25.27 |