| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 43°F | 63°F | 51°F | 3.0" |
| February | 45°F | 63°F | 53°F | 2.6" |
| March | 46°F | 63°F | 54°F | 2.7" |
| April | 47°F | 64°F | 55°F | 1.2" |
| May | 50°F | 65°F | 56°F | 0.3" |
| June | 52°F | 68°F | 59°F | 0.1" |
| July | 54°F | 69°F | 60°F | 0.0" |
| August | 55°F | 69°F | 60°F | 0.1" |
| September | 54°F | 71°F | 61°F | 0.1" |
| October | 51°F | 70°F | 60°F | 1.0" |
| November | 47°F | 66°F | 55°F | 1.6" |
| December | 42°F | 61°F | 51°F | 2.8" |
| Index | Sand City | California | National |
| Air quality index | 37 | 55 | 42 |
| Pollution index | 9,602,130 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 330 |
| Days with moderate air quality | 34 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.070% |
| Benzene | 0.190% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.080% |
| Mercury | 0.070% |
| City | Population | Air Quality Index | National Avg. |
| Castroville, CA | 6,501 | 37 | 26.0% |
| Marina, CA | 22,443 | 37 | 26.0% |
| Prunedale, CA | 20,978 | 37 | 26.0% |
| Boronda, CA | 1,790 | 37 | 26.0% |
| Del Monte Forest, CA | 3,927 | 37 | 26.0% |
| Sand City, CA | 333 | 37 | 26.0% |
| City | Population | Air Quality Index | National Avg. |
| Grangeville, CA | 333 | 56 | 12.0% |
| Milton, IN | 333 | 6 | 88.0% |
| Ransom, KS | 333 | 15 | 70.0% |
| Cerro Gordo, NC | 333 | 30 | 40.0% |
| Niobrara, NE | 333 | 36 | 28.0% |
| Sand City, CA | 333 | 37 | 26.0% |