| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 35°F | 53°F | 44°F | 6.0" |
| February | 40°F | 56°F | 49°F | 6.4" |
| March | 41°F | 57°F | 50°F | 6.8" |
| April | 40°F | 56°F | 49°F | 5.8" |
| May | 45°F | 59°F | 53°F | 3.6" |
| June | 47°F | 61°F | 55°F | 3.9" |
| July | 52°F | 65°F | 58°F | 1.0" |
| August | 50°F | 63°F | 56°F | 0.3" |
| September | 46°F | 63°F | 54°F | 0.4" |
| October | 44°F | 61°F | 53°F | 5.6" |
| November | 40°F | 58°F | 49°F | 4.0" |
| December | 39°F | 54°F | 47°F | 11.4" |
| Index | Fields Landing | California | National |
| Air quality index | 27 | 55 | 42 |
| Pollution index | 5,642,310 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 353 |
| Days with moderate air quality | 10 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.060% |
| Benzene | 0.080% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.050% |
| Mercury | 0.050% |
| City | Population | Air Quality Index | National Avg. |
| Arcata, CA | 18,799 | 27 | 46.0% |
| Eureka, CA | 27,853 | 27 | 46.0% |
| Manila, CA | 790 | 27 | 46.0% |
| Fairhaven, CA | 260 | 27 | 46.0% |
| Samoa, CA | 219 | 27 | 46.0% |
| Fields Landing, CA | 601 | 27 | 46.0% |
| City | Population | Air Quality Index | National Avg. |
| Fort Jones, CA | 601 | 36 | 28.0% |
| Menlo, GA | 601 | 40 | 20.0% |
| Whitesburg, GA | 601 | 52 | 4.0% |
| Kooskia, ID | 601 | 29 | 42.0% |
| Irvington, IL | 601 | 43 | 14.0% |
| Fields Landing, CA | 601 | 27 | 46.0% |