| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 34°F | 54°F | 42°F | 5.1" |
| February | 34°F | 57°F | 44°F | 4.7" |
| March | 41°F | 65°F | 52°F | 5.6" |
| April | 50°F | 75°F | 61°F | 6.5" |
| May | 58°F | 81°F | 69°F | 8.0" |
| June | 67°F | 89°F | 77°F | 7.6" |
| July | 70°F | 91°F | 79°F | 9.7" |
| August | 69°F | 89°F | 77°F | 6.7" |
| September | 63°F | 83°F | 71°F | 9.5" |
| October | 51°F | 74°F | 61°F | 3.5" |
| November | 41°F | 64°F | 51°F | 6.0" |
| December | 37°F | 58°F | 46°F | 6.5" |
| Index | Smithfield | North Carolina | National |
| Air quality index | 40 | 35 | 42 |
| Pollution index | 227,321 | 2,789,538 | 2,726,193 |
| Measurement | Total |
| Days measured | 359 |
| Days with good air quality | 237 |
| Days with moderate air quality | 122 |
| Days w/ poor A.Q. for sensitive groups | |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.003% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Four Oaks, NC | 2,225 | 40 | 20.0% |
| Princeton, NC | 1,396 | 40 | 20.0% |
| Kenly, NC | 2,385 | 40 | 20.0% |
| Selma, NC | 6,950 | 40 | 20.0% |
| Micro, NC | 688 | 40 | 20.0% |
| Smithfield, NC | 12,697 | 40 | 20.0% |
| City | Population | Air Quality Index | National Avg. |
| Fulton, MO | 12,696 | 38 | 24.0% |
| Crowley, LA | 12,689 | 41 | 18.0% |
| St. Ann, MO | 12,689 | 54 | 8.0% |
| Echelon, NJ | 12,687 | 51 | 2.0% |
| Fort Bliss, TX | 12,709 | 53 | 6.0% |
| Smithfield, NC | 12,697 | 40 | 20.0% |
Here are the best places to live in North Carolina
These are the 10 cheapest cities in North Carolina
These are the largest cities in North Carolina
Check out the 10 safest cities in North Carolina