| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 7°F | 26°F | 15°F | 0.8" |
| February | 10°F | 27°F | 17°F | 1.4" |
| March | 24°F | 44°F | 32°F | 2.6" |
| April | 35°F | 58°F | 45°F | 6.4" |
| May | 49°F | 71°F | 58°F | 6.6" |
| June | 60°F | 80°F | 69°F | 8.9" |
| July | 62°F | 85°F | 73°F | 5.8" |
| August | 58°F | 82°F | 68°F | 7.5" |
| September | 53°F | 78°F | 63°F | 5.3" |
| October | 40°F | 63°F | 50°F | 6.0" |
| November | 26°F | 46°F | 34°F | 2.2" |
| December | 11°F | 26°F | 18°F | 1.2" |
| Index | Goodwill | South Dakota | National |
| Air quality index | 25 | 36 | 42 |
| Pollution index | 439,993 | 345,623 | 2,726,193 |
| Measurement | Total |
| Days measured | 361 |
| Days with good air quality | 325 |
| Days with moderate air quality | 36 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Wilmot, SD | 554 | 25 | 50.0% |
| Peever, SD | 186 | 25 | 50.0% |
| Agency Village, SD | 970 | 25 | 50.0% |
| Long Hollow, SD | 395 | 25 | 50.0% |
| Browns Valley, MN | 595 | 25 | 50.0% |
| Goodwill, SD | 696 | 25 | 50.0% |
| City | Population | Air Quality Index | National Avg. |
| Aguanga, CA | 696 | 89 | 78.0% |
| Suttons Bay, MI | 696 | 36 | 28.0% |
| Mora, NM | 696 | 15 | 70.0% |
| Puryear, TN | 696 | 44 | 12.0% |
| Dahlgren Center, VA | 696 | 47 | 6.0% |
| Goodwill, SD | 696 | 25 | 50.0% |
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