| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 45°F | 66°F | 54°F | 5.0" |
| February | 47°F | 69°F | 57°F | 5.2" |
| March | 53°F | 75°F | 64°F | 5.4" |
| April | 60°F | 81°F | 71°F | 5.1" |
| May | 67°F | 86°F | 76°F | 5.7" |
| June | 74°F | 91°F | 82°F | 6.3" |
| July | 75°F | 92°F | 83°F | 6.7" |
| August | 76°F | 93°F | 83°F | 8.5" |
| September | 73°F | 90°F | 81°F | 5.5" |
| October | 62°F | 83°F | 72°F | 3.3" |
| November | 52°F | 74°F | 62°F | 2.3" |
| December | 48°F | 68°F | 57°F | 6.8" |
| Index | Norco | Louisiana | National |
| Air quality index | 45 | 106 | 42 |
| Pollution index | 3,359,480 | 2,526,475 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 229 |
| Days with moderate air quality | 134 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.070% |
| Mercury | 0.100% |
| City | Population | Air Quality Index | National Avg. |
| Garyville, LA | 2,022 | 30 | 40.0% |
| Reserve, LA | 8,721 | 30 | 40.0% |
| Laplace, LA | 29,883 | 30 | 40.0% |
| Des Allemands, LA | 2,053 | 41 | 18.0% |
| Killona, LA | 635 | 41 | 18.0% |
| Norco, LA | 3,110 | 45 | 10.0% |
| City | Population | Air Quality Index | National Avg. |
| Leesburg, GA | 3,110 | 40 | 20.0% |
| Sainte-Mélanie, QC | 3,110 | n/a | |
| Troy, TX | 3,109 | 38 | 24.0% |
| Soda Springs, ID | 3,111 | 27 | 46.0% |
| Agua Fria, NM | 3,111 | 44 | 12.0% |
| Norco, LA | 3,110 | 45 | 10.0% |