| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 44°F | 70°F | 56°F | 1.6" |
| February | 45°F | 72°F | 57°F | 1.2" |
| March | 47°F | 75°F | 60°F | 0.7" |
| April | 50°F | 78°F | 63°F | 0.5" |
| May | 55°F | 82°F | 66°F | 0.2" |
| June | 59°F | 89°F | 72°F | 0.0" |
| July | 65°F | 94°F | 77°F | 0.2" |
| August | 65°F | 95°F | 78°F | 0.1" |
| September | 63°F | 94°F | 76°F | 0.2" |
| October | 56°F | 85°F | 69°F | 0.2" |
| November | 49°F | 77°F | 62°F | 0.5" |
| December | 44°F | 69°F | 55°F | 1.9" |
| Index | La Plaza | San Bernardino | California |
| Air quality index | 89 | 89 | 55 |
| Pollution index | 31,575,300 | 31,575,300 | 10,473,190 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 42 |
| Days with moderate air quality | 178 |
| Days w/ poor A.Q. for sensitive groups | 79 |
| Days with unhealthy air quality | 58 |
| Pollutant | Total |
| Arsenic | 0.110% |
| Benzene | 0.260% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.350% |
| Mercury | 0.280% |
| City | Population | Air Quality Index | National Avg. |
| Colton, CA | 54,215 | 89 | 78.0% |
| Loma Linda, CA | 24,239 | 89 | 78.0% |
| Riverside, CA | 327,569 | 89 | 78.0% |
| Highland, CA | 55,339 | 89 | 78.0% |
| Running Springs, CA | 4,410 | 89 | 78.0% |
| San Bernardino, CA | 216,784 | 89 | 78.0% |
| City | Population | Air Quality Index | National Avg. |
| Tacoma, WA | 215,766 | 18 | 64.0% |
| Des Moines, IA | 215,408 | 39 | 22.0% |
| Richmond Hill, ON | 215,407 | n/a | |
| Spring Valley, NV | 218,697 | 54 | 8.0% |
| Enterprise, NV | 214,591 | 54 | 8.0% |
| San Bernardino, CA | 216,784 | 89 | 78.0% |
Here are the best places to live in California
Check out the 10 safest cities in California
These are the 10 most affordable cities in California
10 best cities to buy a new house in California