| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 4°F | 28°F | 15°F | 0.1" |
| February | 7°F | 30°F | 17°F | 0.2" |
| March | 19°F | 46°F | 31°F | 0.4" |
| April | 30°F | 61°F | 44°F | 0.9" |
| May | 40°F | 71°F | 55°F | 2.6" |
| June | 49°F | 80°F | 65°F | 2.7" |
| July | 56°F | 90°F | 73°F | 1.7" |
| August | 53°F | 88°F | 70°F | 1.9" |
| September | 43°F | 77°F | 59°F | 1.0" |
| October | 31°F | 60°F | 44°F | 0.9" |
| November | 17°F | 44°F | 29°F | 0.2" |
| December | 4°F | 27°F | 14°F | 0.2" |
| Index | Brockton | Montana | National |
| Air quality index | 34 | 34 | 42 |
| Pollution index | 192,968 | 834,473 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 309 |
| Days with moderate air quality | 53 |
| Days w/ poor A.Q. for sensitive groups | 3 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.002% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Poplar, MT | 971 | 34 | 32.0% |
| Brockton, MT | 341 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Midland, AR | 341 | 36 | 28.0% |
| Shirley, AR | 341 | 36 | 28.0% |
| Edmundson Acres, CA | 341 | 67 | 34.0% |
| Mad River, CA | 341 | 27 | 46.0% |
| Richfield, CA | 341 | 41 | 18.0% |
| Brockton, MT | 341 | 34 | 32.0% |
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