Dorchester, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.6 °C (low) to 23.2 °C (high). Annual precipitation averages 1062 Millimeters. Dorchester is located in USDA Plant Hardiness Zone 8a. 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 | -0.1 °C | 11.6 °C | 60.2 mm |
| February | 1.9 °C | 13.9 °C | 70.87 mm |
| March | 6.1 °C | 18.4 °C | 95.5 mm |
| April | 10.4 °C | 22.7 °C | 92.96 mm |
| May | 15.7 °C | 26.7 °C | 134.62 mm |
| June | 20.7 °C | 31.4 °C | 103.63 mm |
| July | 23.1 °C | 34.2 °C | 65.79 mm |
| August | 22.9 °C | 34.5 °C | 67.06 mm |
| September | 18.6 °C | 30.2 °C | 88.14 mm |
| October | 12.2 °C | 24.3 °C | 116.59 mm |
| November | 6.1 °C | 17.9 °C | 82.3 mm |
| December | 1.2 °C | 12.7 °C | 84.33 mm |
| Annual | 11.6 °C | 23.2 °C | 1061.99 mm |
| 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 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |