| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 11°F | 30°F | 20°F | 0.2" |
| February | 13°F | 34°F | 22°F | 0.4" |
| March | 26°F | 49°F | 36°F | 0.8" |
| April | 37°F | 62°F | 48°F | 2.2" |
| May | 48°F | 73°F | 60°F | 3.6" |
| June | 59°F | 83°F | 71°F | 3.3" |
| July | 64°F | 89°F | 76°F | 2.9" |
| August | 61°F | 84°F | 72°F | 3.2" |
| September | 52°F | 78°F | 64°F | 1.9" |
| October | 40°F | 64°F | 50°F | 2.2" |
| November | 26°F | 49°F | 36°F | 0.4" |
| December | 13°F | 32°F | 22°F | 0.5" |
| Index | Harrison | South Dakota | National |
| Air quality index | 36 | 36 | 42 |
| Pollution index | 296,415 | 345,623 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 321 |
| Days with moderate air quality | 43 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.005% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Corsica, SD | 729 | 36 | 28.0% |
| Geddes, SD | 187 | 36 | 28.0% |
| New Holland, SD | 8 | 36 | 28.0% |
| Armour, SD | 653 | 36 | 28.0% |
| Stickney, SD | 265 | 36 | 28.0% |
| Harrison, SD | 7 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Healy Lake, AK | 7 | 38 | 24.0% |
| Livengood, AK | 7 | 38 | 24.0% |
| Corley, IA | 7 | 40 | 20.0% |
| Radium, KS | 7 | 15 | 70.0% |
| Donaldson, MN | 7 | 33 | 34.0% |
| Harrison, SD | 7 | 36 | 28.0% |
Here are the best places to live in South Dakota
Check out the 10 most dangerous cities in South Dakota
See the best places to live in Harrison
Check out the 10 safest cities in South Dakota