| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 33°F | 46°F | 39°F | 11.2" |
| February | 33°F | 51°F | 41°F | 4.9" |
| March | 39°F | 57°F | 46°F | 10.0" |
| April | 40°F | 58°F | 47°F | 5.4" |
| May | 45°F | 65°F | 54°F | 9.8" |
| June | 49°F | 68°F | 57°F | 5.4" |
| July | 53°F | 78°F | 64°F | 3.9" |
| August | 51°F | 78°F | 63°F | 2.6" |
| September | 46°F | 69°F | 56°F | 3.2" |
| October | 43°F | 60°F | 50°F | 5.9" |
| November | 36°F | 48°F | 41°F | 9.2" |
| December | 33°F | 44°F | 38°F | 23.1" |
| Index | Chico | Washington | National |
| Air quality index | 18 | 36 | 42 |
| Pollution index | 1,081,430 | 4,541,850 | 2,726,193 |
| Measurement | Total |
| Days measured | 340 |
| Days with good air quality | 338 |
| Days with moderate air quality | 2 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Keyport, WA | 339 | 18 | 64.0% |
| Silverdale, WA | 21,858 | 18 | 64.0% |
| Southworth, WA | 2,300 | 18 | 64.0% |
| Quilcene, WA | 664 | 18 | 64.0% |
| Gorst, WA | 255 | 18 | 64.0% |
| Chico, WA | 3,184 | 18 | 64.0% |
| City | Population | Air Quality Index | National Avg. |
| Casa Conejo, CA | 3,184 | 46 | 8.0% |
| Tisdale, SK | 3,184 | n/a | |
| Penrose, CO | 3,185 | 16 | 68.0% |
| Verona, MS | 3,185 | 39 | 22.0% |
| Lesslie, SC | 3,185 | 49 | 2.0% |
| Chico, WA | 3,184 | 18 | 64.0% |
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