| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 38°F | 30°F | 4.6" |
| February | 17°F | 33°F | 25°F | 1.6" |
| March | 26°F | 46°F | 36°F | 2.8" |
| April | 37°F | 58°F | 47°F | 5.3" |
| May | 45°F | 71°F | 58°F | 3.7" |
| June | 58°F | 82°F | 70°F | 4.2" |
| July | 58°F | 82°F | 70°F | 7.6" |
| August | 60°F | 81°F | 70°F | 5.0" |
| September | 54°F | 76°F | 64°F | 4.8" |
| October | 47°F | 65°F | 55°F | 4.5" |
| November | 33°F | 50°F | 42°F | 6.0" |
| December | 24°F | 36°F | 30°F | 3.1" |
| Index | Ashtabula | Ohio | National |
| Air quality index | 34 | 40 | 42 |
| Pollution index | 3,205,550 | 4,472,386 | 2,726,193 |
| Measurement | Total |
| Days measured | 358 |
| Days with good air quality | 334 |
| Days with moderate air quality | 23 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| 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. |
| Geneva-on-the-Lake, OH | 978 | 34 | 32.0% |
| Jefferson, OH | 3,359 | 34 | 32.0% |
| North Kingsville, OH | 2,805 | 34 | 32.0% |
| Madison, OH | 3,166 | 34 | 32.0% |
| Conneaut, OH | 12,524 | 34 | 32.0% |
| Ashtabula, OH | 18,067 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Eastlake, OH | 18,072 | 50 | = 100 |
| North Druid Hills, GA | 18,074 | 52 | 4.0% |
| Pelham, ON | 18,077 | n/a | |
| Avon, IN | 18,056 | 54 | 8.0% |
| Saint-Basile-le-Grand, QC | 18,054 | n/a | |
| Ashtabula, OH | 18,067 | 34 | 32.0% |
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