| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 38°F | 64°F | 50°F | 2.9" |
| February | 39°F | 66°F | 51°F | 3.7" |
| March | 45°F | 72°F | 58°F | 3.1" |
| April | 53°F | 80°F | 66°F | 3.4" |
| May | 62°F | 85°F | 73°F | 3.4" |
| June | 70°F | 91°F | 79°F | 6.6" |
| July | 73°F | 92°F | 82°F | 6.5" |
| August | 73°F | 91°F | 81°F | 8.0" |
| September | 68°F | 87°F | 76°F | 5.9" |
| October | 56°F | 80°F | 67°F | 5.6" |
| November | 45°F | 72°F | 57°F | 2.9" |
| December | 42°F | 67°F | 53°F | 3.7" |
| Index | Hanahan | South Carolina | National |
| Air quality index | 38 | 37 | 42 |
| Pollution index | 783,589 | 3,620,438 | 2,726,193 |
| Measurement | Total |
| Days measured | 355 |
| Days with good air quality | 299 |
| Days with moderate air quality | 55 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| James Island, SC | 12,157 | 38 | 24.0% |
| North Charleston, SC | 113,880 | 38 | 24.0% |
| Summerville, SC | 53,643 | 38 | 24.0% |
| Hollywood, SC | 5,273 | 38 | 24.0% |
| Ladson, SC | 15,252 | 38 | 24.0% |
| Hanahan, SC | 25,743 | 38 | 24.0% |
| City | Population | Air Quality Index | National Avg. |
| Green, OH | 25,737 | 43 | 14.0% |
| Laurel, MD | 25,734 | 47 | 6.0% |
| Beloeil, QC | 25,755 | n/a | |
| White Bear Lake, MN | 25,718 | 46 | 8.0% |
| Owatonna, MN | 25,716 | 36 | 28.0% |
| Hanahan, SC | 25,743 | 38 | 24.0% |
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