| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 38°F | 59°F | 47°F | 2.6" |
| February | 41°F | 63°F | 51°F | 2.6" |
| March | 43°F | 67°F | 54°F | 2.1" |
| April | 45°F | 72°F | 57°F | 1.4" |
| May | 50°F | 78°F | 62°F | 0.3" |
| June | 54°F | 85°F | 67°F | 0.2" |
| July | 58°F | 90°F | 71°F | 0.0" |
| August | 57°F | 89°F | 70°F | 0.0" |
| September | 56°F | 88°F | 69°F | 0.1" |
| October | 50°F | 79°F | 63°F | 0.9" |
| November | 43°F | 67°F | 54°F | 1.5" |
| December | 38°F | 60°F | 48°F | 2.8" |
| Index | Mountain House | California | National |
| Air quality index | 57 | 55 | 50 |
| Pollution index | 13,698,500 | 18,106,726 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 128 |
| Days with moderate air quality | 207 |
| Days w/ poor A.Q. for sensitive groups | 21 |
| Days with unhealthy air quality | 9 |
| Pollutant | Total |
| Arsenic | 0.040% |
| Benzene | 0.110% |
| Carbon Tetrachloride | 0.330% |
| Lead | 0.070% |
| Mercury | 0.120% |
| City, State | Population | Air Quality Index | National Avg. |
| Livermore, CA | 86,493 | 48 | 4% |
| Byron, CA | 1,429 | 57 | 14% |
| Knightsen, CA | 1,606 | 57 | 14% |
| Taft Mosswood, CA | 936 | 57 | 14% |
| Country Club, CA | 9,597 | 57 | 14% |
| Mountain House, CA | 14,009 | 57 | 14% |
| City, State | Population | Air Quality Index | National Avg. |
| Elizabethton, TN | 14,012 | 45 | 10% |
| Washington, MO | 14,012 | 60 | 20% |
| Indiana, PA | 14,002 | 36 | 28% |
| Maumee, OH | 14,018 | 36 | 28% |
| Oldsmar, FL | 14,023 | 43 | 14% |
| Mountain House, CA | 14,009 | 57 | 14% |