| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 30°F | 53°F | 41°F | 5.0" |
| February | 32°F | 56°F | 43°F | 3.9" |
| March | 39°F | 65°F | 51°F | 5.2" |
| April | 47°F | 75°F | 60°F | 6.7" |
| May | 56°F | 80°F | 68°F | 5.4" |
| June | 64°F | 88°F | 76°F | 9.1" |
| July | 68°F | 90°F | 78°F | 5.9" |
| August | 68°F | 89°F | 77°F | 9.7" |
| September | 61°F | 83°F | 71°F | 8.7" |
| October | 48°F | 73°F | 59°F | 8.8" |
| November | 37°F | 63°F | 49°F | 6.5" |
| December | 35°F | 57°F | 44°F | 6.2" |
| Index | Holly Springs | North Carolina | National |
| Air quality index | 46 | 35 | 42 |
| Pollution index | 1,387,180 | 2,789,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 239 |
| Days with moderate air quality | 126 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.004% |
| Lead | 0.010% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Moncure, NC | 823 | 29 | 42.0% |
| Broadway, NC | 1,510 | 29 | 42.0% |
| Morrisville, NC | 28,305 | 44 | 12.0% |
| Fearrington Village, NC | 2,787 | 44 | 12.0% |
| Fuquay-Varina, NC | 29,773 | 46 | 8.0% |
| Holly Springs, NC | 37,538 | 46 | 8.0% |
| City | Population | Air Quality Index | National Avg. |
| Lewiston, ME | 37,532 | 31 | 38.0% |
| Phenix City, AL | 37,524 | 42 | 16.0% |
| Dunedin, FL | 37,553 | 43 | 14.0% |
| Portage, IN | 37,504 | 37 | 26.0% |
| Roseville, MN | 37,577 | 46 | 8.0% |
| Holly Springs, NC | 37,538 | 46 | 8.0% |