| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 33°F | 56°F | 44°F | 3.4" |
| February | 35°F | 59°F | 46°F | 2.8" |
| March | 42°F | 68°F | 54°F | 3.3" |
| April | 50°F | 77°F | 63°F | 2.7" |
| May | 58°F | 83°F | 70°F | 3.1" |
| June | 67°F | 90°F | 78°F | 3.1" |
| July | 70°F | 92°F | 80°F | 2.8" |
| August | 69°F | 91°F | 79°F | 3.4" |
| September | 63°F | 85°F | 73°F | 3.0" |
| October | 50°F | 76°F | 62°F | 3.3" |
| November | 39°F | 66°F | 51°F | 3.1" |
| December | 37°F | 59°F | 47°F | 5.0" |
| Index | Joanna | South Carolina | National |
| Air quality index | 44 | 37 | 42 |
| Pollution index | 1,755,840 | 3,620,438 | 2,726,193 |
| Measurement | Total |
| Days measured | 357 |
| Days with good air quality | 249 |
| Days with moderate air quality | 106 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.010% |
| Mercury | 0.003% |
| City | Population | Air Quality Index | National Avg. |
| Waterloo, SC | 181 | 31 | 38.0% |
| Cross Hill, SC | 556 | 31 | 38.0% |
| Silverstreet, SC | 159 | 43 | 14.0% |
| Newberry, SC | 10,219 | 43 | 14.0% |
| Whitmire, SC | 1,641 | 44 | 12.0% |
| Joanna, SC | 1,270 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Fruitland, IA | 1,270 | 32 | 36.0% |
| Beaverton, MI | 1,270 | 26 | 48.0% |
| Fincastle, TN | 1,270 | 39 | 22.0% |
| Lake Bryan, TX | 1,270 | 38 | 24.0% |
| Susitna North, AK | 1,271 | 31 | 38.0% |
| Joanna, SC | 1,270 | 44 | 12.0% |
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