| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 21°F | 36°F | 28°F | 3.3" |
| February | 19°F | 36°F | 27°F | 2.8" |
| March | 26°F | 46°F | 36°F | 3.0" |
| April | 37°F | 59°F | 48°F | 3.2" |
| May | 48°F | 70°F | 59°F | 3.7" |
| June | 58°F | 79°F | 68°F | 4.3" |
| July | 63°F | 82°F | 73°F | 4.3" |
| August | 62°F | 81°F | 72°F | 4.2" |
| September | 56°F | 75°F | 65°F | 4.8" |
| October | 46°F | 64°F | 54°F | 5.4" |
| November | 36°F | 53°F | 44°F | 3.9" |
| December | 27°F | 41°F | 34°F | 4.4" |
| Index | Union City | Pennsylvania | National |
| Air quality index | 36 | 45 | 42 |
| Pollution index | 3,205,550 | 4,584,805 | 2,726,193 |
| Measurement | Total |
| Days measured | 364 |
| Days with good air quality | 322 |
| Days with moderate air quality | 42 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.170% |
| Mercury | 0.005% |
| City | Population | Air Quality Index | National Avg. |
| Spartansburg, PA | 286 | 9 | 82.0% |
| Cambridge Springs, PA | 2,667 | 36 | 28.0% |
| Canadohta Lake, PA | 433 | 36 | 28.0% |
| Edinboro, PA | 5,599 | 36 | 28.0% |
| Saegertown, PA | 1,172 | 36 | 28.0% |
| Union City, PA | 3,148 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Haviland, NY | 3,148 | 36 | 28.0% |
| Grand Saline, TX | 3,148 | 36 | 28.0% |
| Cashmere, WA | 3,148 | 24 | 52.0% |
| Wesleyville, PA | 3,147 | 36 | 28.0% |
| Hamburg, NJ | 3,149 | 34 | 32.0% |
| Union City, PA | 3,148 | 36 | 28.0% |
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