| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 44°F | 65°F | 53°F | 5.2" |
| February | 45°F | 66°F | 54°F | 5.0" |
| March | 51°F | 74°F | 62°F | 3.1" |
| April | 58°F | 80°F | 68°F | 3.2" |
| May | 66°F | 86°F | 75°F | 5.7" |
| June | 72°F | 92°F | 81°F | 3.0" |
| July | 74°F | 92°F | 82°F | 5.2" |
| August | 74°F | 93°F | 82°F | 7.9" |
| September | 70°F | 89°F | 78°F | 6.9" |
| October | 58°F | 81°F | 69°F | 5.6" |
| November | 49°F | 73°F | 59°F | 2.7" |
| December | 45°F | 66°F | 54°F | 9.3" |
| Index | Montpelier | Louisiana | National |
| Air quality index | 30 | 106 | 42 |
| Pollution index | 498,493 | 2,526,475 | 2,726,193 |
| Measurement | Total |
| Days measured | 117 |
| Days with good air quality | 104 |
| Days with moderate air quality | 13 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.004% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.004% |
| Mercury | 0.002% |
| City | Population | Air Quality Index | National Avg. |
| Greensburg, LA | 1,042 | 30 | 40.0% |
| Natalbany, LA | 2,958 | 30 | 40.0% |
| Hammond, LA | 21,033 | 30 | 40.0% |
| Roseland, LA | 1,221 | 30 | 40.0% |
| Albany, LA | 1,342 | 30 | 40.0% |
| Montpelier, LA | 332 | 30 | 40.0% |
| City | Population | Air Quality Index | National Avg. |
| Eldorado Springs, CO | 332 | 47 | 6.0% |
| Silver City, IA | 332 | 40 | 20.0% |
| Oldtown, ID | 332 | 43 | 14.0% |
| Winslow, IL | 332 | 29 | 42.0% |
| Rosemont, MD | 332 | 40 | 20.0% |
| Montpelier, LA | 332 | 30 | 40.0% |