| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 40°F | 29°F | 0.3" |
| February | 20°F | 41°F | 30°F | 0.6" |
| March | 27°F | 51°F | 38°F | 0.9" |
| April | 31°F | 58°F | 43°F | 1.8" |
| May | 37°F | 66°F | 51°F | 3.1" |
| June | 44°F | 77°F | 61°F | 2.0" |
| July | 50°F | 90°F | 70°F | 1.0" |
| August | 48°F | 87°F | 68°F | 1.1" |
| September | 41°F | 77°F | 58°F | 1.3" |
| October | 35°F | 61°F | 47°F | 1.6" |
| November | 26°F | 48°F | 37°F | 0.8" |
| December | 17°F | 36°F | 26°F | 0.6" |
| Index | Greycliff | Montana | National |
| Air quality index | 21 | 34 | 42 |
| Pollution index | 218,962 | 834,473 | 2,726,193 |
| Measurement | Total |
| Days measured | 362 |
| Days with good air quality | 357 |
| Days with moderate air quality | 4 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 1 |
| 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. |
| Reed Point, MT | 247 | 21 | 58.0% |
| Big Timber, MT | 1,736 | 25 | 50.0% |
| Greycliff, MT | 133 | 21 | 58.0% |
| City | Population | Air Quality Index | National Avg. |
| Aleknagik, AK | 133 | 31 | 38.0% |
| Dutch Flat, CA | 133 | 44 | 12.0% |
| Volta, CA | 133 | 48 | 4.0% |
| Bradgate, IA | 133 | 15 | 70.0% |
| Floris, IA | 133 | 29 | 42.0% |
| Greycliff, MT | 133 | 21 | 58.0% |
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