| 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 | Portland | Oregon | National |
| Air quality index | 38 | 32 | 42 |
| Pollution index | 1,899,410 | 7,156,356 | 2,726,193 |
| 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% |
| Fern Prairie, WA | 1,989 | 38 | 24.0% |
| Washougal, WA | 15,927 | 38 | 24.0% |
| Garden Home-Whitford, OR | 7,295 | 38 | 24.0% |
| Lake Oswego, OR | 39,476 | 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
Safest States In The US
Check out the 10 most dangerous cities in Oregon
Check out the 10 safest cities in Oregon