| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 31°F | 55°F | 42°F | 2.7" |
| February | 31°F | 58°F | 44°F | 2.6" |
| March | 39°F | 67°F | 52°F | 4.3" |
| April | 48°F | 76°F | 62°F | 4.1" |
| May | 56°F | 82°F | 68°F | 4.1" |
| June | 65°F | 90°F | 77°F | 4.8" |
| July | 69°F | 93°F | 80°F | 5.2" |
| August | 69°F | 91°F | 79°F | 4.9" |
| September | 62°F | 85°F | 72°F | 5.5" |
| October | 49°F | 75°F | 61°F | 3.4" |
| November | 38°F | 66°F | 51°F | 3.8" |
| December | 34°F | 58°F | 45°F | 4.1" |
| Index | Morrisville | North Carolina | National |
| Air quality index | 44 | 35 | 42 |
| Pollution index | 2,015,140 | 2,789,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 275 |
| Days with moderate air quality | 90 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.000% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Moncure, NC | 823 | 29 | 42.0% |
| Carrboro, NC | 22,056 | 44 | 12.0% |
| Chapel Hill, NC | 64,145 | 44 | 12.0% |
| Durham, NC | 285,434 | 44 | 12.0% |
| Fearrington Village, NC | 2,787 | 44 | 12.0% |
| Morrisville, NC | 28,305 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Round Lake Beach, IL | 28,313 | 39 | 22.0% |
| Mint Hill, NC | 28,318 | 49 | 2.0% |
| Easton, PA | 28,264 | 42 | 16.0% |
| Mililani Town, HI | 28,249 | 30 | 40.0% |
| Fort Saskatchewan, AB | 28,368 | n/a | |
| Morrisville, NC | 28,305 | 44 | 12.0% |