| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 22°F | 35°F | 29°F | 0.7" |
| February | 26°F | 45°F | 35°F | 0.6" |
| March | 32°F | 57°F | 44°F | 1.1" |
| April | 38°F | 65°F | 52°F | 0.8" |
| May | 47°F | 76°F | 62°F | 0.7" |
| June | 54°F | 83°F | 69°F | 0.8" |
| July | 61°F | 92°F | 77°F | 0.2" |
| August | 60°F | 91°F | 76°F | 0.2" |
| September | 50°F | 81°F | 65°F | 0.3" |
| October | 40°F | 65°F | 52°F | 0.9" |
| November | 29°F | 48°F | 38°F | 0.8" |
| December | 22°F | 37°F | 30°F | 0.9" |
| Index | Mansfield | Washington | National |
| Air quality index | 24 | 36 | 42 |
| Pollution index | 2,683,410 | 4,541,850 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 298 |
| Days with moderate air quality | 66 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.004% |
| Lead | 0.030% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Bridgeport, WA | 2,657 | 24 | 52.0% |
| Mansfield, WA | 305 | 24 | 52.0% |
| City | Population | Air Quality Index | National Avg. |
| Harding-Birch Lakes, AK | 305 | 38 | 24.0% |
| Elfrida, AZ | 305 | 45 | 10.0% |
| Grenada, CA | 305 | 36 | 28.0% |
| Ceylon, MN | 305 | 15 | 70.0% |
| Vesta, MN | 305 | 32 | 36.0% |
| Mansfield, WA | 305 | 24 | 52.0% |