| 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 | Tustin | California | National |
| Air quality index | 89 | 55 | 42 |
| Pollution index | 44,192,600 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 42 |
| Days with moderate air quality | 178 |
| Days w/ poor A.Q. for sensitive groups | 79 |
| Days with unhealthy air quality | 58 |
| Pollutant | Total |
| Arsenic | 0.030% |
| Benzene | 0.280% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.220% |
| Mercury | 0.140% |
| City | Population | Air Quality Index | National Avg. |
| Cypress, CA | 49,137 | 72 | 44.0% |
| La Palma, CA | 15,657 | 72 | 44.0% |
| Stanton, CA | 38,317 | 72 | 44.0% |
| Huntington Beach, CA | 199,778 | 72 | 44.0% |
| Fullerton, CA | 141,061 | 72 | 44.0% |
| Tustin, CA | 80,815 | 89 | 78.0% |
| City | Population | Air Quality Index | National Avg. |
| Deerfield Beach, FL | 80,822 | 41 | 18.0% |
| Auburn, WA | 80,914 | 45 | 10.0% |
| Farmington Hills, MI | 80,937 | 56 | 12.0% |
| Franklin, TN | 80,675 | 45 | 10.0% |
| Lynchburg, VA | 80,970 | 26 | 48.0% |
| Tustin, CA | 80,815 | 89 | 78.0% |
Here are the best places to live in California
Top 10 cities in California with the best education system
10 Best cities in California for employment
These are the 10 most affordable cities in California