| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 35°F | 45°F | 40°F | 1.2" |
| February | 37°F | 48°F | 41°F | 2.3" |
| March | 40°F | 51°F | 45°F | 2.5" |
| April | 42°F | 56°F | 48°F | 0.6" |
| May | 46°F | 61°F | 53°F | 1.2" |
| June | 50°F | 66°F | 57°F | 0.9" |
| July | 52°F | 71°F | 60°F | 0.0" |
| August | 52°F | 71°F | 61°F | 0.0" |
| September | 50°F | 66°F | 57°F | 0.5" |
| October | 45°F | 57°F | 51°F | 2.9" |
| November | 40°F | 50°F | 44°F | 2.4" |
| December | 35°F | 44°F | 39°F | 1.4" |
| Index | Big Lake | Washington | National |
| Air quality index | 24 | 36 | 42 |
| Pollution index | 15,778,900 | 4,541,850 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 361 |
| Days with moderate air quality | 4 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.270% |
| Carbon Tetrachloride | 0.040% |
| Lead | 0.160% |
| Mercury | 0.003% |
| City | Population | Air Quality Index | National Avg. |
| Bay View, WA | 686 | 24 | 52.0% |
| Arlington, WA | 20,435 | 24 | 52.0% |
| Lyman, WA | 289 | 24 | 52.0% |
| Conway, WA | 42 | 24 | 52.0% |
| Northwest Stanwood, WA | 82 | 24 | 52.0% |
| Big Lake, WA | 2,325 | 24 | 52.0% |
| City | Population | Air Quality Index | National Avg. |
| Madison, NE | 2,325 | 35 | 30.0% |
| Mesilla, NM | 2,325 | 51 | 2.0% |
| Whitehall, NY | 2,324 | 36 | 28.0% |
| Brewster, NY | 2,327 | 36 | 28.0% |
| Central Okanagan J, BC | 2,327 | n/a | |
| Big Lake, WA | 2,325 | 24 | 52.0% |