| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 33°F | 24°F | 2.8" |
| February | 20°F | 37°F | 27°F | 3.3" |
| March | 33°F | 55°F | 43°F | 3.3" |
| April | 42°F | 63°F | 51°F | 6.4" |
| May | 53°F | 74°F | 63°F | 7.9" |
| June | 63°F | 82°F | 72°F | 9.5" |
| July | 66°F | 87°F | 76°F | 3.7" |
| August | 67°F | 87°F | 76°F | 10.2" |
| September | 57°F | 79°F | 67°F | 7.1" |
| October | 46°F | 66°F | 55°F | 5.5" |
| November | 32°F | 52°F | 41°F | 3.2" |
| December | 18°F | 33°F | 25°F | 3.4" |
| Index | Sun Valley Lake | Iowa | National |
| Air quality index | 39 | 39 | 50 |
| Pollution index | 1,469,540 | 1,643,836 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 306 |
| Days with moderate air quality | 59 |
| 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 | 0.002% |
| Mercury | 0.000% |
| City, State | Population | Air Quality Index | National Avg. |
| Decatur City, IA | 205 | 39 | 22% |
| Van Wert, IA | 190 | 39 | 22% |
| Shannon City, IA | 54 | 39 | 22% |
| Afton, IA | 967 | 39 | 22% |
| Diagonal, IA | 319 | 39 | 22% |
| Sun Valley Lake, IA | 224 | 39 | 22% |
| City, State | Population | Air Quality Index | National Avg. |
| Alderpoint, CA | 224 | 27 | 46% |
| Earl, NC | 224 | 36 | 28% |
| Colerain, NC | 224 | 0 | 100% |
| Riverdale, ND | 224 | 36 | 28% |
| Silver City, IA | 224 | 40 | 20% |
| Sun Valley Lake, IA | 224 | 39 | 22% |
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