| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 24°F | 37°F | 30°F | 2.8" |
| February | 28°F | 46°F | 35°F | 2.1" |
| March | 34°F | 54°F | 43°F | 2.0" |
| April | 36°F | 59°F | 47°F | 1.8" |
| May | 43°F | 69°F | 55°F | 2.0" |
| June | 46°F | 73°F | 59°F | 2.0" |
| July | 51°F | 88°F | 70°F | 0.9" |
| August | 48°F | 86°F | 67°F | 1.2" |
| September | 41°F | 73°F | 56°F | 1.4" |
| October | 39°F | 61°F | 49°F | 2.4" |
| November | 31°F | 45°F | 37°F | 2.7" |
| December | 24°F | 35°F | 30°F | 2.9" |
| Index | De Smet | Idaho | National |
| Air quality index | 10 | 32 | 42 |
| Pollution index | 1,107,360 | 2,063,710 | 2,726,193 |
| Measurement | Total |
| Days measured | 350 |
| Days with good air quality | 350 |
| Days with moderate air quality | 0 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.004% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Tensed, ID | 69 | 10 | 80.0% |
| Onaway, ID | 212 | 10 | 80.0% |
| Farmington, WA | 146 | 10 | 80.0% |
| Garfield, WA | 605 | 18 | 64.0% |
| Tekoa, WA | 798 | 18 | 64.0% |
| De Smet, ID | 163 | 10 | 80.0% |
| City | Population | Air Quality Index | National Avg. |
| Deepstep, GA | 163 | 38 | 24.0% |
| Bentley, IA | 163 | 40 | 20.0% |
| Calumet, IA | 163 | 35 | 30.0% |
| Shambaugh, IA | 163 | 43 | 14.0% |
| Dunreith, IN | 163 | 28 | 44.0% |
| De Smet, ID | 163 | 10 | 80.0% |