| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 41°F | 68°F | 53°F | 3.9" |
| February | 43°F | 67°F | 54°F | 2.6" |
| March | 45°F | 69°F | 55°F | 2.2" |
| April | 47°F | 71°F | 57°F | 1.4" |
| May | 49°F | 73°F | 59°F | 0.3" |
| June | 52°F | 77°F | 62°F | 0.1" |
| July | 55°F | 79°F | 64°F | 0.1" |
| August | 56°F | 80°F | 64°F | 0.0" |
| September | 55°F | 82°F | 65°F | 0.0" |
| October | 52°F | 80°F | 63°F | 0.9" |
| November | 46°F | 73°F | 57°F | 1.1" |
| December | 41°F | 66°F | 52°F | 3.1" |
| Index | San Luis Obispo | California | National |
| Air quality index | 56 | 55 | 50 |
| Pollution index | 5,611,110 | 18,106,726 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 129 |
| Days with moderate air quality | 227 |
| Days w/ poor A.Q. for sensitive groups | 8 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.020% |
| Benzene | 0.060% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.060% |
| Mercury | 0.010% |
| City, State | Population | Air Quality Index | National Avg. |
| Callender, CA | 1,814 | 56 | 12% |
| Grover Beach, CA | 13,484 | 56 | 12% |
| Morro Bay, CA | 10,519 | 56 | 12% |
| Arroyo Grande, CA | 17,842 | 56 | 12% |
| Cayucos, CA | 2,987 | 56 | 12% |
| San Luis Obispo, CA | 46,716 | 56 | 12% |
| City, State | Population | Air Quality Index | National Avg. |
| Palm Springs, CA | 46,714 | 85 | 70% |
| Twin Falls, ID | 46,623 | 13 | 74% |
| Texas City, TX | 46,811 | 52 | 4% |
| North Highlands, CA | 46,841 | 55 | 10% |
| Hattiesburg, MS | 46,846 | 39 | 22% |
| San Luis Obispo, CA | 46,716 | 56 | 12% |