| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 35°F | 48°F | 40°F | 5.6" |
| February | 37°F | 52°F | 43°F | 4.0" |
| March | 39°F | 57°F | 47°F | 5.4" |
| April | 41°F | 62°F | 51°F | 3.2" |
| May | 47°F | 70°F | 57°F | 2.6" |
| June | 52°F | 76°F | 62°F | 1.4" |
| July | 55°F | 85°F | 69°F | 0.4" |
| August | 55°F | 85°F | 69°F | 0.4" |
| September | 51°F | 79°F | 63°F | 1.7" |
| October | 45°F | 65°F | 54°F | 4.3" |
| November | 40°F | 54°F | 46°F | 6.4" |
| December | 34°F | 47°F | 40°F | 6.1" |
| Index | Donald | Oregon | National |
| Air quality index | 32 | 32 | 42 |
| Pollution index | 11,541,100 | 7,156,356 | 2,726,193 |
| Measurement | Total |
| Days measured | 356 |
| Days with good air quality | 302 |
| Days with moderate air quality | 54 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.140% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.020% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Labish Village, OR | 505 | 32 | 36.0% |
| Woodburn, OR | 26,769 | 32 | 36.0% |
| Dayton, OR | 2,834 | 32 | 36.0% |
| Brooks, OR | 638 | 32 | 36.0% |
| Lafayette, OR | 4,353 | 32 | 36.0% |
| Donald, OR | 1,499 | 32 | 36.0% |
| City | Population | Air Quality Index | National Avg. |
| Fosston, MN | 1,499 | 33 | 34.0% |
| Alpine, NJ | 1,499 | 51 | 2.0% |
| Eagle Butte, SD | 1,499 | 44 | 12.0% |
| New Paris, IN | 1,498 | 37 | 26.0% |
| Burlington, ND | 1,500 | 34 | 32.0% |
| Donald, OR | 1,499 | 32 | 36.0% |