| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 25°F | 38°F | 31°F | 2.0" |
| February | 28°F | 43°F | 34°F | 1.4" |
| March | 32°F | 52°F | 41°F | 2.4" |
| April | 36°F | 61°F | 47°F | 1.3" |
| May | 43°F | 72°F | 57°F | 1.2" |
| June | 50°F | 78°F | 64°F | 2.0" |
| July | 57°F | 90°F | 73°F | 0.5" |
| August | 55°F | 88°F | 71°F | 0.4" |
| September | 47°F | 78°F | 61°F | 0.6" |
| October | 39°F | 62°F | 49°F | 1.7" |
| November | 32°F | 47°F | 39°F | 2.0" |
| December | 25°F | 37°F | 30°F | 2.4" |
| Index | Rockwood | Spokane | Washington |
| Air quality index | 43 | 43 | 36 |
| Pollution index | 2,233,350 | 2,233,350 | 4,541,850 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 252 |
| Days with moderate air quality | 111 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.003% |
| Mercury | 0.001% |
| City | Population | Air Quality Index | National Avg. |
| Airway Heights, WA | 8,885 | 43 | 14.0% |
| Medical Lake, WA | 4,950 | 43 | 14.0% |
| Mead, WA | 6,995 | 43 | 14.0% |
| Spangle, WA | 231 | 43 | 14.0% |
| Cheney, WA | 12,455 | 43 | 14.0% |
| Spokane, WA | 219,185 | 43 | 14.0% |
| City | Population | Air Quality Index | National Avg. |
| Spring Valley, NV | 218,697 | 54 | 8.0% |
| San Bernardino, CA | 216,784 | 89 | 78.0% |
| Baton Rouge, LA | 222,191 | 45 | 10.0% |
| Richmond, BC | 222,489 | n/a | |
| Tacoma, WA | 215,766 | 18 | 64.0% |
| Spokane, WA | 219,185 | 43 | 14.0% |
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