| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 37°F | 60°F | 47°F | 5.6" |
| February | 41°F | 64°F | 52°F | 4.8" |
| March | 45°F | 69°F | 56°F | 4.6" |
| April | 47°F | 74°F | 60°F | 2.5" |
| May | 52°F | 82°F | 67°F | 0.7" |
| June | 57°F | 91°F | 74°F | 0.3" |
| July | 60°F | 96°F | 77°F | 0.0" |
| August | 59°F | 95°F | 75°F | 0.0" |
| September | 56°F | 92°F | 73°F | 0.1" |
| October | 50°F | 81°F | 64°F | 1.9" |
| November | 43°F | 68°F | 54°F | 2.3" |
| December | 37°F | 59°F | 47°F | 4.6" |
| Index | Hartley | California | National |
| Air quality index | 35 | 55 | 42 |
| Pollution index | 2,457,150 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 330 |
| Days with moderate air quality | 31 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.080% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.010% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Allendale, CA | 1,429 | 35 | 30.0% |
| Lemon Hill, CA | 15,104 | 35 | 30.0% |
| Winters, CA | 7,285 | 35 | 30.0% |
| Fairfield, CA | 116,544 | 35 | 30.0% |
| Moskowite Corner, CA | 69 | 35 | 30.0% |
| Hartley, CA | 2,655 | 35 | 30.0% |
| City | Population | Air Quality Index | National Avg. |
| Casey, IL | 2,655 | 40 | 20.0% |
| Wabasha, MN | 2,655 | 15 | 70.0% |
| Woodstock, NY | 2,655 | 36 | 28.0% |
| Shadybrook, TX | 2,655 | 36 | 28.0% |
| Berwick, NS | 2,655 | n/a | |
| Hartley, CA | 2,655 | 35 | 30.0% |
Here are the best places to live in California
These are the 10 cheapest cities in California
Safest States In The US
Check out the 10 most dangerous cities in California