| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 44°F | 68°F | 56°F | 1.6" |
| February | 45°F | 68°F | 56°F | 1.7" |
| March | 47°F | 70°F | 58°F | 1.1" |
| April | 50°F | 71°F | 60°F | 0.7" |
| May | 55°F | 72°F | 62°F | 0.4" |
| June | 58°F | 76°F | 65°F | 0.0" |
| July | 63°F | 80°F | 69°F | 0.1" |
| August | 63°F | 81°F | 70°F | 0.0" |
| September | 61°F | 81°F | 70°F | 0.2" |
| October | 56°F | 79°F | 66°F | 0.5" |
| November | 50°F | 74°F | 61°F | 0.9" |
| December | 44°F | 67°F | 55°F | 2.0" |
| Index | Spring Valley CDP (Lake County) | California | National |
| Air quality index | 64 | 55 | 42 |
| Pollution index | 45,820,500 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 87 |
| Days with moderate air quality | 253 |
| Days w/ poor A.Q. for sensitive groups | 23 |
| Days with unhealthy air quality | 2 |
| Pollutant | Total |
| Arsenic | 1.130% |
| Benzene | 0.410% |
| Carbon Tetrachloride | 0.030% |
| Lead | 0.600% |
| Mercury | 0.080% |
| City | Population | Air Quality Index | National Avg. |
| Imperial Beach, CA | 27,334 | 64 | 28.0% |
| National City, CA | 61,342 | 64 | 28.0% |
| Bostonia, CA | 17,532 | 64 | 28.0% |
| Eucalyptus Hills, CA | 6,448 | 64 | 28.0% |
| La Mesa, CA | 60,208 | 64 | 28.0% |
| Spring Valley CDP (Lake County), CA | 1,154 | 64 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Astoria, IL | 1,154 | 40 | 20.0% |
| Hatfield, MA | 1,154 | 40 | 20.0% |
| West Kennebunk, ME | 1,154 | 40 | 20.0% |
| Urbancrest, OH | 1,154 | 46 | 8.0% |
| Richlandtown, PA | 1,154 | 42 | 16.0% |
| Spring Valley CDP (Lake County), CA | 1,154 | 64 | 28.0% |
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