| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 41°F | 58°F | 49°F | 2.3" |
| February | 44°F | 63°F | 52°F | 0.6" |
| March | 50°F | 68°F | 58°F | 0.5" |
| April | 59°F | 75°F | 67°F | 2.2" |
| May | 67°F | 82°F | 74°F | 6.5" |
| June | 74°F | 88°F | 81°F | 3.0" |
| July | 76°F | 90°F | 82°F | 5.3" |
| August | 75°F | 89°F | 81°F | 3.9" |
| September | 70°F | 85°F | 77°F | 4.9" |
| October | 60°F | 78°F | 68°F | 0.7" |
| November | 48°F | 68°F | 56°F | 0.8" |
| December | 46°F | 63°F | 53°F | 3.8" |
| Index | Rockville | 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. |
| Folly Beach, SC | 2,664 | 38 | 24.0% |
| Ravenel, SC | 2,650 | 38 | 24.0% |
| James Island, SC | 12,157 | 38 | 24.0% |
| Seabrook Island, SC | 1,810 | 38 | 24.0% |
| Edisto Beach, SC | 710 | 38 | 24.0% |
| Rockville, SC | 132 | 38 | 24.0% |
| City | Population | Air Quality Index | National Avg. |
| Yellow Bluff, AL | 132 | 52 | 4.0% |
| Vallecito, CA | 132 | 39 | 22.0% |
| Otter Creek, FL | 132 | 35 | 30.0% |
| Blockton, IA | 132 | 43 | 14.0% |
| Geneva, IA | 132 | 15 | 70.0% |
| Rockville, SC | 132 | 38 | 24.0% |
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