| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 39°F | 58°F | 48°F | 3.3" |
| February | 43°F | 62°F | 52°F | 3.0" |
| March | 45°F | 67°F | 54°F | 1.8" |
| April | 47°F | 71°F | 57°F | 1.9" |
| May | 52°F | 78°F | 63°F | 0.6" |
| June | 56°F | 85°F | 68°F | 0.0" |
| July | 58°F | 90°F | 71°F | 0.0" |
| August | 57°F | 90°F | 70°F | 0.0" |
| September | 56°F | 86°F | 68°F | 0.0" |
| October | 50°F | 77°F | 62°F | 1.4" |
| November | 45°F | 68°F | 55°F | 1.2" |
| December | 40°F | 57°F | 47°F | 2.3" |
| Index | Contra Costa Centre | California | National |
| Air quality index | 40 | 55 | 42 |
| Pollution index | 13,698,500 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 290 |
| Days with moderate air quality | 74 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.040% |
| Benzene | 0.110% |
| Carbon Tetrachloride | 0.330% |
| Lead | 0.070% |
| Mercury | 0.120% |
| City | Population | Air Quality Index | National Avg. |
| Acalanes Ridge, CA | 875 | 40 | 20.0% |
| Concord, CA | 129,227 | 40 | 20.0% |
| Orinda, CA | 19,461 | 40 | 20.0% |
| San Miguel, CA | 3,253 | 40 | 20.0% |
| Vine Hill, CA | 3,228 | 40 | 20.0% |
| Contra Costa Centre, CA | 6,667 | 40 | 20.0% |
| City | Population | Air Quality Index | National Avg. |
| Medfield, MA | 6,668 | 43 | 14.0% |
| South Bay, FL | 6,665 | 36 | 28.0% |
| Church Hill, TN | 6,664 | 45 | 10.0% |
| Sunnyvale, TX | 6,664 | 51 | 2.0% |
| Hamilton, AL | 6,662 | 39 | 22.0% |
| Contra Costa Centre, CA | 6,667 | 40 | 20.0% |
Here are the best places to live in California
Most Dangerous Cities In The US
These are the 10 cheapest cities in California
Check out the 10 safest cities in California