| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 24°F | 40°F | 31°F | 1.0" |
| February | 26°F | 44°F | 34°F | 1.4" |
| March | 31°F | 53°F | 40°F | 3.4" |
| April | 33°F | 57°F | 44°F | 1.9" |
| May | 39°F | 67°F | 52°F | 2.8" |
| June | 44°F | 72°F | 57°F | 5.3" |
| July | 52°F | 87°F | 69°F | 1.2" |
| August | 50°F | 88°F | 69°F | 2.8" |
| September | 45°F | 80°F | 61°F | 3.8" |
| October | 36°F | 60°F | 47°F | 2.4" |
| November | 29°F | 47°F | 37°F | 2.0" |
| December | 24°F | 37°F | 30°F | 1.6" |
| Index | Riggins | Idaho | National |
| Air quality index | 29 | 32 | 42 |
| Pollution index | 1,490,030 | 2,063,710 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 291 |
| Days with moderate air quality | 73 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.020% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Riggins, ID | 235 | 29 | 42.0% |
| City | Population | Air Quality Index | National Avg. |
| Grady, AR | 235 | 45 | 10.0% |
| Cambridge, ID | 235 | 36 | 28.0% |
| Pryorsburg, KY | 235 | 44 | 12.0% |
| Nanticoke, MD | 235 | 41 | 18.0% |
| Big Spring, MO | 235 | 39 | 22.0% |
| Riggins, ID | 235 | 29 | 42.0% |