| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 34°F | 48°F | 40°F | 4.9" |
| February | 36°F | 53°F | 43°F | 3.4" |
| March | 39°F | 58°F | 48°F | 4.8" |
| April | 42°F | 63°F | 52°F | 3.0" |
| May | 48°F | 71°F | 58°F | 2.8" |
| June | 53°F | 76°F | 63°F | 1.7" |
| July | 57°F | 84°F | 69°F | 0.5" |
| August | 58°F | 85°F | 70°F | 0.5" |
| September | 53°F | 78°F | 64°F | 1.8" |
| October | 47°F | 66°F | 55°F | 3.7" |
| November | 40°F | 55°F | 47°F | 6.2" |
| December | 34°F | 47°F | 40°F | 6.2" |
| Index | Hillsdale | Portland | Oregon |
| Air quality index | 38 | 38 | 32 |
| Pollution index | 3,247,580 | 1,899,410 | 7,156,356 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 285 |
| Days with moderate air quality | 77 |
| Days w/ poor A.Q. for sensitive groups | 3 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.003% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.010% |
| Mercury | 0.002% |
| City | Population | Air Quality Index | National Avg. |
| Troutdale, OR | 16,433 | 38 | 24.0% |
| Orchards, WA | 26,289 | 38 | 24.0% |
| Garden Home-Whitford, OR | 7,295 | 38 | 24.0% |
| King City, OR | 4,345 | 38 | 24.0% |
| Oak Grove, OR | 17,781 | 38 | 24.0% |
| Portland, OR | 650,380 | 38 | 24.0% |
| City | Population | Air Quality Index | National Avg. |
| Memphis, TN | 650,910 | 45 | 10.0% |
| Oklahoma City, OK | 649,821 | 48 | 4.0% |
| Las Vegas, NV | 644,594 | 54 | 8.0% |
| Nashville, TN | 667,070 | 45 | 10.0% |
| Detroit, MI | 672,351 | 56 | 12.0% |
| Portland, OR | 650,380 | 38 | 24.0% |
Here are the best places to live in Oregon
These are the 10 cheapest cities in Oregon
Check out the 10 most dangerous cities in Oregon
See the best places to live in Portland