| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 36°F | 58°F | 47°F | 3.8" |
| February | 39°F | 62°F | 50°F | 3.4" |
| March | 41°F | 66°F | 52°F | 3.0" |
| April | 42°F | 69°F | 55°F | 1.6" |
| May | 46°F | 74°F | 59°F | 0.5" |
| June | 50°F | 80°F | 64°F | 0.3" |
| July | 53°F | 81°F | 65°F | 0.0" |
| August | 53°F | 80°F | 64°F | 0.0" |
| September | 49°F | 82°F | 64°F | 0.1" |
| October | 45°F | 76°F | 59°F | 1.3" |
| November | 40°F | 66°F | 52°F | 1.8" |
| December | 36°F | 58°F | 47°F | 3.8" |
| Index | Sonoma | California | National |
| Air quality index | 35 | 55 | 50 |
| Pollution index | 7,898,290 | 18,106,726 | 5,066,862 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 330 |
| Days with moderate air quality | 31 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.260% |
| Benzene | 0.080% |
| Carbon Tetrachloride | 0.005% |
| Lead | 0.240% |
| Mercury | 0.270% |
| City, State | Population | Air Quality Index | National Avg. |
| Roseland, CA | 5,859 | 34 | 32% |
| Penngrove, CA | 2,940 | 34 | 32% |
| Cotati, CA | 7,415 | 34 | 32% |
| Glen Ellen, CA | 726 | 34 | 32% |
| Petaluma, CA | 59,757 | 34 | 32% |
| Sonoma, CA | 10,952 | 35 | 30% |
| City, State | Population | Air Quality Index | National Avg. |
| South Yarmouth, MA | 10,953 | 36 | 28% |
| Lighthouse Point, FL | 10,946 | 41 | 18% |
| White House, TN | 10,944 | 45 | 10% |
| Dent, OH | 10,963 | 54 | 8% |
| Fairfield, AL | 10,937 | 53 | 6% |
| Sonoma, CA | 10,952 | 35 | 30% |
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