| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 12°F | 36°F | 23°F | 0.3" |
| February | 14°F | 40°F | 25°F | 0.5" |
| March | 24°F | 53°F | 37°F | 0.9" |
| April | 33°F | 63°F | 47°F | 2.0" |
| May | 43°F | 72°F | 57°F | 2.9" |
| June | 54°F | 84°F | 68°F | 3.2" |
| July | 61°F | 94°F | 77°F | 1.5" |
| August | 58°F | 91°F | 73°F | 1.8" |
| September | 48°F | 82°F | 64°F | 1.0" |
| October | 36°F | 65°F | 49°F | 1.5" |
| November | 23°F | 52°F | 36°F | 0.4" |
| December | 11°F | 35°F | 22°F | 1.1" |
| Index | Midland | South Dakota | National |
| Air quality index | 44 | 36 | 42 |
| Pollution index | 123,501 | 345,623 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 274 |
| Days with moderate air quality | 87 |
| Days w/ poor A.Q. for sensitive groups | 4 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.001% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.010% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Okaton, SD | 49 | 44 | 12.0% |
| Midland, SD | 120 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Oakhaven, AR | 120 | 39 | 22.0% |
| Fernan Lake Village, ID | 120 | 43 | 14.0% |
| Gem, KS | 120 | 19 | 62.0% |
| Republic, KS | 120 | 19 | 62.0% |
| Cearfoss, MD | 120 | 40 | 20.0% |
| Midland, SD | 120 | 44 | 12.0% |