| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 48°F | 70°F | 58°F | 3.5" |
| February | 50°F | 70°F | 59°F | 2.9" |
| March | 52°F | 72°F | 61°F | 1.5" |
| April | 55°F | 74°F | 63°F | 0.7" |
| May | 58°F | 75°F | 65°F | 0.5" |
| June | 61°F | 78°F | 68°F | 0.0" |
| July | 65°F | 83°F | 72°F | 0.0" |
| August | 65°F | 84°F | 73°F | 0.0" |
| September | 64°F | 85°F | 72°F | 0.3" |
| October | 60°F | 81°F | 69°F | 0.7" |
| November | 54°F | 75°F | 63°F | 0.8" |
| December | 48°F | 69°F | 57°F | 2.8" |
| Index | Monrovia | California | National |
| Air quality index | 72 | 55 | 42 |
| Pollution index | 139,490,000 | 10,473,190 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 66 |
| Days with moderate air quality | 208 |
| Days w/ poor A.Q. for sensitive groups | 62 |
| Days with unhealthy air quality | 28 |
| Pollutant | Total |
| Arsenic | 0.200% |
| Benzene | 0.950% |
| Carbon Tetrachloride | 0.080% |
| Lead | 1.320% |
| Mercury | 0.440% |
| City | Population | Air Quality Index | National Avg. |
| Azusa, CA | 49,584 | 72 | 44.0% |
| Citrus, CA | 10,105 | 72 | 44.0% |
| Irwindale, CA | 1,365 | 72 | 44.0% |
| Valinda, CA | 22,665 | 72 | 44.0% |
| West Puente Valley, CA | 23,555 | 72 | 44.0% |
| Monrovia, CA | 37,636 | 72 | 44.0% |
| City | Population | Air Quality Index | National Avg. |
| Rock Island, IL | 37,651 | 46 | 8.0% |
| Carpentersville, IL | 37,618 | 55 | 10.0% |
| Menomonee Falls, WI | 37,611 | 44 | 12.0% |
| Clinton, MD | 37,765 | 47 | 6.0% |
| Egypt Lake-Leto, FL | 37,775 | 43 | 14.0% |
| Monrovia, CA | 37,636 | 72 | 44.0% |
Here are the best places to live in California
Check out the 10 most dangerous cities in California
These are the largest cities in California
Most Dangerous States In The US