Union Valley, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 54.3 °F (low) to 76 °F (high). Annual precipitation averages 42.4 Inches. Union Valley is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 34.5 °F | 55.9 °F | 2.81 in. |
| February | 38.1 °F | 60.0 °F | 3.14 in. |
| March | 45.4 °F | 67.5 °F | 3.88 in. |
| April | 52.8 °F | 75.1 °F | 3.71 in. |
| May | 62.5 °F | 82.4 °F | 4.92 in. |
| June | 70.4 °F | 90.3 °F | 3.91 in. |
| July | 73.5 °F | 94.3 °F | 2.19 in. |
| August | 72.9 °F | 95.2 °F | 2.5 in. |
| September | 65.9 °F | 88.7 °F | 3.15 in. |
| October | 54.8 °F | 78.5 °F | 4.96 in. |
| November | 44.5 °F | 66.6 °F | 3.57 in. |
| December | 36.5 °F | 57.8 °F | 3.63 in. |
| Annual | 54.3 °F | 76 °F | 42.37 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |