| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 35°F | 56°F | 45°F | 6.9" |
| February | 33°F | 55°F | 43°F | 4.8" |
| March | 41°F | 67°F | 53°F | 7.5" |
| April | 47°F | 73°F | 59°F | 5.2" |
| May | 54°F | 79°F | 67°F | 2.6" |
| June | 65°F | 86°F | 75°F | 10.3" |
| July | 69°F | 89°F | 78°F | 7.2" |
| August | 71°F | 93°F | 81°F | 5.1" |
| September | 63°F | 87°F | 74°F | 3.8" |
| October | 54°F | 76°F | 64°F | 10.6" |
| November | 39°F | 66°F | 52°F | 2.9" |
| December | 35°F | 57°F | 45°F | 7.2" |
| Index | Monroe | North Carolina | National |
| Air quality index | 42 | 35 | 50 |
| Pollution index | 2,035,010 | 3,848,988 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 278 |
| Days with moderate air quality | 87 |
| Days w/ poor A.Q. for sensitive groups | |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.020% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.010% |
| Mercury | 0.004% |
| City, State | Population | Air Quality Index | National Avg. |
| Hemby Bridge, NC | 1,264 | 42 | 16% |
| Marshville, NC | 2,598 | 42 | 16% |
| Mint Hill, NC | 25,024 | 42 | 16% |
| Weddington, NC | 10,254 | 42 | 16% |
| Indian Trail, NC | 36,357 | 42 | 16% |
| Monroe, NC | 34,212 | 42 | 16% |
| City, State | Population | Air Quality Index | National Avg. |
| Vestavia Hills, AL | 34,243 | 50 | = 100 |
| Wentzville, MO | 34,176 | 60 | 20% |
| Evans, GA | 34,270 | 42 | 16% |
| Cottonwood Heights, UT | 34,274 | 47 | 6% |
| Oildale, CA | 34,277 | 79 | 58% |
| Monroe, NC | 34,212 | 42 | 16% |