| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 41°F | 59°F | 50°F | 2.8" |
| February | 45°F | 62°F | 53°F | 3.1" |
| March | 47°F | 65°F | 55°F | 2.9" |
| April | 49°F | 67°F | 57°F | 1.8" |
| May | 52°F | 69°F | 59°F | 0.4" |
| June | 54°F | 72°F | 62°F | 0.3" |
| July | 56°F | 73°F | 63°F | 0.0" |
| August | 57°F | 73°F | 63°F | 0.0" |
| September | 55°F | 76°F | 64°F | 0.1" |
| October | 52°F | 73°F | 61°F | 1.0" |
| November | 47°F | 65°F | 56°F | 1.9" |
| December | 42°F | 59°F | 50°F | 4.1" |
| Index | Jefferson | Oakland | California |
| Air quality index | 40 | 40 | 55 |
| Pollution index | 19,202,400 | 19,202,400 | 10,473,190 |
| 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 | 0.180% |
| Benzene | 0.140% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.280% |
| Mercury | 0.060% |
| City | Population | Air Quality Index | National Avg. |
| Walnut Creek, CA | 69,836 | 40 | 20.0% |
| Alamo, CA | 13,864 | 40 | 20.0% |
| Contra Costa Centre, CA | 6,667 | 40 | 20.0% |
| Pacheco, CA | 4,775 | 40 | 20.0% |
| San Miguel CDP (San Luis Obispo County), CA | 2,696 | 40 | 20.0% |
| Oakland, CA | 422,575 | 40 | 20.0% |
| City | Population | Air Quality Index | National Avg. |
| London, ON | 421,456 | n/a | |
| Minneapolis, MN | 424,536 | 46 | 8.0% |
| Tulsa, OK | 402,441 | 45 | 10.0% |
| Laval, QC | 445,050 | n/a | |
| Arlington, TX | 397,269 | 51 | 2.0% |
| Oakland, CA | 422,575 | 40 | 20.0% |
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