| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 33°F | 47°F | 39°F | 7.4" |
| February | 33°F | 51°F | 41°F | 4.9" |
| March | 36°F | 55°F | 44°F | 6.1" |
| April | 38°F | 60°F | 48°F | 4.0" |
| May | 44°F | 67°F | 55°F | 4.5" |
| June | 49°F | 72°F | 60°F | 3.0" |
| July | 52°F | 80°F | 65°F | 1.5" |
| August | 52°F | 80°F | 65°F | 3.4" |
| September | 48°F | 73°F | 60°F | 4.4" |
| October | 42°F | 62°F | 51°F | 6.3" |
| November | 36°F | 52°F | 44°F | 8.2" |
| December | 32°F | 46°F | 38°F | 6.9" |
| Index | Summit | Washington | National |
| Air quality index | 30 | 36 | 42 |
| Pollution index | 17,693,800 | 4,541,850 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 323 |
| Days with moderate air quality | 42 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.300% |
| Carbon Tetrachloride | 0.050% |
| Lead | 0.110% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Dash Point, WA | 1,008 | 18 | 64.0% |
| Rosedale, WA | 4,389 | 18 | 64.0% |
| Tacoma, WA | 215,766 | 18 | 64.0% |
| Browns Point, WA | 961 | 18 | 64.0% |
| Wollochet, WA | 7,193 | 18 | 64.0% |
| Summit, WA | 8,993 | 30 | 40.0% |
| City | Population | Air Quality Index | National Avg. |
| Spanish Fort, AL | 8,991 | 37 | 26.0% |
| Micco, FL | 8,990 | 36 | 28.0% |
| Brandywine, MD | 8,990 | 47 | 6.0% |
| Fairview, TN | 8,989 | 45 | 10.0% |
| Lock Haven, PA | 8,997 | 35 | 30.0% |
| Summit, WA | 8,993 | 30 | 40.0% |
Here are the best places to live in Washington
Most Dangerous States In The US
See the best places to live in Summit
These are the 10 cheapest cities in Washington