| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 48°F | 69°F | 57°F | 2.3" |
| February | 49°F | 69°F | 58°F | 1.9" |
| March | 52°F | 70°F | 60°F | 0.9" |
| April | 54°F | 72°F | 62°F | 0.6" |
| May | 59°F | 73°F | 65°F | 0.3" |
| June | 62°F | 76°F | 67°F | 0.0" |
| July | 66°F | 80°F | 71°F | 0.1" |
| August | 66°F | 82°F | 72°F | 0.0" |
| September | 65°F | 82°F | 72°F | 0.2" |
| October | 60°F | 79°F | 68°F | 0.5" |
| November | 54°F | 75°F | 63°F | 0.7" |
| December | 48°F | 68°F | 57°F | 2.4" |
| Index | Walnut Village | Irvine | California |
| Air quality index | 85 | 85 | 55 |
| Pollution index | 44,192,600 | 44,192,600 | 18,106,726 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 24 |
| Days with moderate air quality | 211 |
| Days w/ poor A.Q. for sensitive groups | 102 |
| Days with unhealthy air quality | 25 |
| Pollutant | Total |
| Arsenic | 0.030% |
| Benzene | 0.280% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.220% |
| Mercury | 0.140% |
| City, State | Population | Air Quality Index | National Avg. |
| Buena Park, CA | 82,771 | 74 | 48% |
| Fullerton, CA | 139,491 | 74 | 48% |
| Cypress, CA | 48,978 | 74 | 48% |
| Garden Grove, CA | 174,676 | 74 | 48% |
| La Mirada, CA | 49,130 | 74 | 48% |
| Irvine, CA | 246,992 | 85 | 70% |
| City, State | Population | Air Quality Index | National Avg. |
| Madison, WI | 246,034 | 42 | 16% |
| Norfolk, VA | 245,724 | 39 | 22% |
| Lubbock, TX | 244,507 | 26 | 48% |
| Laredo, TX | 251,671 | 38 | 24% |
| Durham, NC | 251,761 | 35 | 30% |
| Irvine, CA | 246,992 | 85 | 70% |