| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 32°F | 59°F | 43°F | 1.0" |
| February | 36°F | 64°F | 48°F | 1.1" |
| March | 46°F | 73°F | 57°F | 0.8" |
| April | 53°F | 81°F | 65°F | 1.1" |
| May | 61°F | 86°F | 72°F | 1.5" |
| June | 70°F | 94°F | 81°F | 1.6" |
| July | 73°F | 97°F | 85°F | 1.3" |
| August | 73°F | 98°F | 84°F | 1.2" |
| September | 65°F | 90°F | 76°F | 2.7" |
| October | 54°F | 81°F | 66°F | 1.8" |
| November | 44°F | 69°F | 55°F | 0.5" |
| December | 34°F | 59°F | 44°F | 0.6" |
| Index | Newcastle | Texas | National |
| Air quality index | 26 | 52 | 42 |
| Pollution index | 406,090 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 345 |
| Days with good air quality | 308 |
| Days with moderate air quality | 37 |
| Days w/ poor A.Q. for sensitive groups | |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Graham, TX | 8,618 | 26 | 48.0% |
| Elbert, TX | 7 | 26 | 48.0% |
| Olney, TX | 3,098 | 26 | 48.0% |
| Newcastle, TX | 577 | 26 | 48.0% |
| City | Population | Air Quality Index | National Avg. |
| Fields Landing, CA | 577 | 27 | 46.0% |
| Chaplin, KY | 577 | 49 | 2.0% |
| Cedarville, MD | 577 | 47 | 6.0% |
| Oak Hill, MI | 577 | 36 | 28.0% |
| Martinsburg, MO | 577 | 38 | 24.0% |
| Newcastle, TX | 577 | 26 | 48.0% |
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