Newcastle, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11 °C (low) to 25.1 °C (high). Annual precipitation averages 774.2 Millimeters. Newcastle 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 | -0.8 °C | 13.7 °C | 33.78 mm |
| February | 1.1 °C | 15.7 °C | 44.2 mm |
| March | 5.6 °C | 20.4 °C | 61.21 mm |
| April | 10 °C | 25.1 °C | 61.98 mm |
| May | 15.7 °C | 29.2 °C | 110.24 mm |
| June | 20.6 °C | 33.3 °C | 93.47 mm |
| July | 22.6 °C | 36.1 °C | 57.4 mm |
| August | 22.1 °C | 36 °C | 58.93 mm |
| September | 17.8 °C | 31.7 °C | 79.25 mm |
| October | 11.4 °C | 26.1 °C | 82.55 mm |
| November | 5.2 °C | 19.4 °C | 49.28 mm |
| December | 0.4 °C | 14.3 °C | 41.91 mm |
| Annual | 11 °C | 25.1 °C | 774.2 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 50-75 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 |