| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 51°F | 35°F | 7.7" |
| February | 27°F | 45°F | 35°F | 4.7" |
| March | 38°F | 65°F | 51°F | 2.9" |
| April | 47°F | 71°F | 58°F | 7.0" |
| May | 56°F | 86°F | 71°F | 1.6" |
| June | 61°F | 90°F | 76°F | 1.1" |
| July | 66°F | 87°F | 77°F | 3.1" |
| August | 66°F | 86°F | 75°F | 6.0" |
| September | 58°F | 79°F | 68°F | 3.3" |
| October | 44°F | 73°F | 59°F | 0.7" |
| November | 35°F | 64°F | 48°F | 2.8" |
| December | 26°F | 53°F | 38°F | 1.7" |
| Index | Harding-Birch Lakes | Alaska | National |
| Air quality index | 38 | 30 | 42 |
| Pollution index | 4,370,560 | 11,243,194 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 230 |
| Days with moderate air quality | 96 |
| Days w/ poor A.Q. for sensitive groups | 18 |
| Days with unhealthy air quality | 16 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.080% |
| Carbon Tetrachloride | 0.004% |
| Lead | 0.090% |
| Mercury | 0.060% |
| City | Population | Air Quality Index | National Avg. |
| Salcha, AK | 964 | 38 | 24.0% |
| Harding-Birch Lakes, AK | 305 | 38 | 24.0% |
| City | Population | Air Quality Index | National Avg. |
| Elfrida, AZ | 305 | 45 | 10.0% |
| Grenada, CA | 305 | 36 | 28.0% |
| Ceylon, MN | 305 | 15 | 70.0% |
| Vesta, MN | 305 | 32 | 36.0% |
| Arcola, MS | 305 | 43 | 14.0% |
| Harding-Birch Lakes, AK | 305 | 38 | 24.0% |