Dennis, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 53.6 °F (low) to 77.8 °F (high). Annual precipitation averages 33.4 Inches. Dennis is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 32.9 °F | 58.1 °F | 1.93 in. |
| February | 37.0 °F | 61.9 °F | 2.37 in. |
| March | 44.7 °F | 69.6 °F | 3.09 in. |
| April | 52.4 °F | 77.6 °F | 2.9 in. |
| May | 62.2 °F | 84.4 °F | 3.85 in. |
| June | 70.3 °F | 92.1 °F | 3.49 in. |
| July | 73.5 °F | 96.6 °F | 1.63 in. |
| August | 72.8 °F | 97.0 °F | 2.53 in. |
| September | 65.3 °F | 89.7 °F | 3.13 in. |
| October | 54.1 °F | 79.6 °F | 3.8 in. |
| November | 43.6 °F | 67.8 °F | 2.52 in. |
| December | 34.9 °F | 59.5 °F | 2.2 in. |
| Annual | 53.6 °F | 77.8 °F | 33.44 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |