| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 38°F | 56°F | 47°F | 6.0" |
| February | 39°F | 56°F | 48°F | 5.3" |
| March | 40°F | 56°F | 48°F | 6.9" |
| April | 40°F | 57°F | 49°F | 3.6" |
| May | 44°F | 59°F | 52°F | 1.2" |
| June | 47°F | 62°F | 55°F | 0.7" |
| July | 50°F | 63°F | 56°F | 0.2" |
| August | 50°F | 64°F | 57°F | 0.2" |
| September | 47°F | 65°F | 56°F | 0.5" |
| October | 45°F | 64°F | 54°F | 3.4" |
| November | 42°F | 59°F | 51°F | 5.2" |
| December | 37°F | 55°F | 47°F | 7.3" |
| Index | Hyampom | California | National |
| Air quality index | 27 | 55 | 42 |
| Pollution index | 5,642,310 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 353 |
| Days with moderate air quality | 10 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.060% |
| Benzene | 0.080% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.050% |
| Mercury | 0.050% |
| City | Population | Air Quality Index | National Avg. |
| Mad River, CA | 355 | 27 | 46.0% |
| Burnt Ranch, CA | 190 | 27 | 46.0% |
| Hayfork, CA | 2,670 | 42 | 16.0% |
| Hyampom, CA | 128 | 27 | 46.0% |
| City | Population | Air Quality Index | National Avg. |
| Cold Bay, AK | 128 | 31 | 38.0% |
| Kokhanok, AK | 128 | 31 | 38.0% |
| Eldridge, AL | 128 | 35 | 30.0% |
| Cold Springs CDP (Tuolumne County), CA | 128 | 52 | 4.0% |
| Nicolaus, CA | 128 | 44 | 12.0% |
| Hyampom, CA | 128 | 27 | 46.0% |