| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 15°F | 39°F | 26°F | 0.2" |
| February | 16°F | 41°F | 27°F | 0.6" |
| March | 27°F | 56°F | 39°F | 1.0" |
| April | 36°F | 63°F | 48°F | 3.1" |
| May | 46°F | 73°F | 59°F | 4.5" |
| June | 58°F | 84°F | 70°F | 3.9" |
| July | 62°F | 88°F | 74°F | 3.3" |
| August | 59°F | 85°F | 71°F | 3.5" |
| September | 50°F | 79°F | 63°F | 2.3" |
| October | 38°F | 65°F | 50°F | 2.4" |
| November | 25°F | 53°F | 37°F | 0.3" |
| December | 14°F | 38°F | 25°F | 0.5" |
| Index | Westerville | Nebraska | National |
| Air quality index | 19 | 86 | 42 |
| Pollution index | 5,232,950 | 590,627 | 2,726,193 |
| Measurement | Total |
| Days measured | 60 |
| Days with good air quality | 55 |
| Days with moderate air quality | 5 |
| Days w/ poor A.Q. for sensitive groups | |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.080% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.010% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Mason City, NE | 163 | 19 | 62.0% |
| Arcadia, NE | 364 | 19 | 62.0% |
| Berwyn, NE | 95 | 19 | 62.0% |
| Comstock, NE | 94 | 19 | 62.0% |
| Broken Bow, NE | 3,503 | 19 | 62.0% |
| Westerville, NE | 0 | 19 | 62.0% |
| City | Population | Air Quality Index | National Avg. |
| Chase, AK | 0 | 31 | 38.0% |
| Chiniak, AK | 0 | 31 | 38.0% |
| Chisana, AK | 0 | 31 | 38.0% |
| Dot Lake, AK | 0 | 38 | 24.0% |
| Eureka Roadhouse, AK | 0 | 31 | 38.0% |
| Westerville, NE | 0 | 19 | 62.0% |
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