Somerville, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.7 °C (low) to 26.7 °C (high). Annual precipitation averages 1073.2 Millimeters. Somerville is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.8 °C | 16.5 °C | 83.31 mm |
| February | 5.8 °C | 18.5 °C | 72.64 mm |
| March | 9.6 °C | 22.3 °C | 82.8 mm |
| April | 13.5 °C | 26.4 °C | 84.58 mm |
| May | 18 °C | 30.2 °C | 124.21 mm |
| June | 21.7 °C | 33.8 °C | 100.33 mm |
| July | 22.8 °C | 35.4 °C | 49.02 mm |
| August | 22.6 °C | 36.2 °C | 83.57 mm |
| September | 19.6 °C | 33.2 °C | 86.87 mm |
| October | 13.9 °C | 28.2 °C | 119.38 mm |
| November | 8.7 °C | 22 °C | 95 mm |
| December | 4.7 °C | 17.6 °C | 91.44 mm |
| Annual | 13.7 °C | 26.7 °C | 1073.15 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |