| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 47°F | 65°F | 55°F | 3.7" |
| February | 49°F | 68°F | 57°F | 2.9" |
| March | 56°F | 74°F | 64°F | 3.6" |
| April | 62°F | 79°F | 70°F | 5.6" |
| May | 70°F | 87°F | 77°F | 4.0" |
| June | 75°F | 92°F | 83°F | 6.0" |
| July | 76°F | 92°F | 83°F | 9.1" |
| August | 77°F | 93°F | 84°F | 5.1" |
| September | 73°F | 89°F | 80°F | 6.1" |
| October | 64°F | 83°F | 72°F | 10.0" |
| November | 55°F | 75°F | 64°F | 3.7" |
| December | 47°F | 66°F | 56°F | 4.0" |
| Index | Mont Belvieu | Texas | National |
| Air quality index | 52 | 52 | 42 |
| Pollution index | 99,643 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 171 |
| Days with moderate air quality | 163 |
| Days w/ poor A.Q. for sensitive groups | 26 |
| Days with unhealthy air quality | 4 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.001% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Ames, TX | 1,106 | 45 | 10.0% |
| Liberty, TX | 9,540 | 45 | 10.0% |
| Anahuac, TX | 2,238 | 45 | 10.0% |
| Beach City, TX | 2,820 | 52 | 4.0% |
| Old River-Winfree, TX | 1,695 | 52 | 4.0% |
| Mont Belvieu, TX | 6,375 | 52 | 4.0% |
| City | Population | Air Quality Index | National Avg. |
| Hazardville, CT | 6,370 | 40 | 20.0% |
| Jackson, OH | 6,381 | 14 | 72.0% |
| Hillsboro, IL | 6,368 | 40 | 20.0% |
| Salem, IN | 6,382 | 35 | 30.0% |
| Orange Beach, AL | 6,366 | 41 | 18.0% |
| Mont Belvieu, TX | 6,375 | 52 | 4.0% |