| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 21°F | 38°F | 29°F | 1.0" |
| February | 27°F | 45°F | 35°F | 0.7" |
| March | 32°F | 56°F | 42°F | 1.1" |
| April | 36°F | 62°F | 48°F | 1.1" |
| May | 43°F | 72°F | 57°F | 1.3" |
| June | 52°F | 83°F | 67°F | 1.0" |
| July | 60°F | 93°F | 76°F | 0.4" |
| August | 58°F | 90°F | 73°F | 0.6" |
| September | 49°F | 80°F | 64°F | 0.6" |
| October | 38°F | 66°F | 51°F | 1.1" |
| November | 28°F | 52°F | 39°F | 0.9" |
| December | 21°F | 39°F | 29°F | 1.4" |
| Index | Castleford | Idaho | National |
| Air quality index | 20 | 32 | 42 |
| Pollution index | 3,377,370 | 2,063,710 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 361 |
| Days with moderate air quality | 4 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.020% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Buhl, ID | 4,462 | 20 | 60.0% |
| Filer, ID | 2,845 | 20 | 60.0% |
| Hollister, ID | 309 | 20 | 60.0% |
| Castleford, ID | 181 | 20 | 60.0% |
| City | Population | Air Quality Index | National Avg. |
| Gulfcrest, AL | 181 | 42 | 16.0% |
| Humnoke, AR | 181 | 45 | 10.0% |
| Beaver Valley, AZ | 181 | 60 | 20.0% |
| Olancha, CA | 181 | 66 | 32.0% |
| Bristow, IA | 181 | 15 | 70.0% |
| Castleford, ID | 181 | 20 | 60.0% |
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