Newcastle, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.7 °C (low) to 22.3 °C (high). Annual precipitation averages 909.3 Millimeters. Newcastle is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.7 °C | 10.1 °C | 33.53 mm |
| February | -0.6 °C | 12.4 °C | 39.37 mm |
| March | 4.2 °C | 17.4 °C | 66.55 mm |
| April | 8.9 °C | 22.1 °C | 90.93 mm |
| May | 14.8 °C | 26.3 °C | 132.33 mm |
| June | 19.7 °C | 31 °C | 113.54 mm |
| July | 21.9 °C | 34.1 °C | 87.12 mm |
| August | 21.2 °C | 33.8 °C | 78.99 mm |
| September | 16.8 °C | 29.4 °C | 87.12 mm |
| October | 10.1 °C | 23.3 °C | 81.53 mm |
| November | 3.7 °C | 16.6 °C | 50.8 mm |
| December | -1.1 °C | 10.9 °C | 47.5 mm |
| Annual | 9.7 °C | 22.3 °C | 909.31 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |