Newcastle, Utah has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 33.6 °F (low) to 65.3 °F (high). Annual precipitation averages 13.3 Inches. Newcastle is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.7 °F | 42.5 °F | 1.22 in. |
| February | 19.9 °F | 46.7 °F | 1.58 in. |
| March | 25.6 °F | 55.7 °F | 1.62 in. |
| April | 29.6 °F | 62.2 °F | 0.92 in. |
| May | 37.6 °F | 71.7 °F | 0.89 in. |
| June | 47.4 °F | 83.6 °F | 0.44 in. |
| July | 55.5 °F | 89.8 °F | 0.83 in. |
| August | 54.2 °F | 87.6 °F | 1.4 in. |
| September | 44.7 °F | 80.4 °F | 1.23 in. |
| October | 33.2 °F | 67.9 °F | 0.96 in. |
| November | 22.6 °F | 53.7 °F | 0.89 in. |
| December | 15.6 °F | 42.2 °F | 1.28 in. |
| Annual | 33.6 °F | 65.3 °F | 13.26 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |