| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 9°F | 29°F | 18°F | 0.7" |
| February | 10°F | 31°F | 19°F | 1.0" |
| March | 22°F | 46°F | 32°F | 1.1" |
| April | 32°F | 59°F | 44°F | 3.5" |
| May | 43°F | 70°F | 55°F | 7.0" |
| June | 52°F | 80°F | 65°F | 5.2" |
| July | 59°F | 88°F | 72°F | 3.7" |
| August | 56°F | 86°F | 69°F | 3.6" |
| September | 46°F | 76°F | 59°F | 3.6" |
| October | 34°F | 59°F | 45°F | 2.2" |
| November | 20°F | 43°F | 30°F | 1.0" |
| December | 8°F | 27°F | 17°F | 0.8" |
| Index | Sidney | Montana | National |
| Air quality index | 34 | 34 | 42 |
| Pollution index | 330,429 | 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 | 0.005% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Fairview, MT | 985 | 34 | 32.0% |
| East Fairview, ND | 93 | 34 | 32.0% |
| Crane, MT | 247 | 34 | 32.0% |
| Sidney, MT | 6,351 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Waveland, MS | 6,352 | 42 | 16.0% |
| Village of Oak Creek (Big Park), AZ | 6,348 | 45 | 10.0% |
| Johnsburg, IL | 6,354 | 39 | 22.0% |
| Ramtown, NJ | 6,354 | 41 | 18.0% |
| Champion Heights, OH | 6,354 | 42 | 16.0% |
| Sidney, MT | 6,351 | 34 | 32.0% |
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