| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 28°F | 47°F | 36°F | 12.8" |
| February | 30°F | 52°F | 40°F | 4.2" |
| March | 40°F | 64°F | 51°F | 2.6" |
| April | 43°F | 67°F | 55°F | 5.3" |
| May | 54°F | 77°F | 65°F | 6.0" |
| June | 63°F | 84°F | 73°F | 6.7" |
| July | 65°F | 89°F | 76°F | 7.8" |
| August | 68°F | 92°F | 79°F | 9.3" |
| September | 60°F | 84°F | 71°F | 6.6" |
| October | 48°F | 73°F | 59°F | 8.2" |
| November | 38°F | 62°F | 49°F | 2.5" |
| December | 27°F | 49°F | 37°F | 4.3" |
| Index | Decatur | Arkansas | National |
| Air quality index | 44 | 38 | 42 |
| Pollution index | 2,124,190 | 1,487,822 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 267 |
| Days with moderate air quality | 98 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.020% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.004% |
| Lead | 0.010% |
| Mercury | 0.200% |
| City | Population | Air Quality Index | National Avg. |
| Dripping Springs, OK | 54 | 36 | 28.0% |
| Colcord, OK | 870 | 36 | 28.0% |
| Noel, MO | 2,051 | 38 | 24.0% |
| Southwest City, MO | 1,064 | 38 | 24.0% |
| Sycamore, OK | 0 | 38 | 24.0% |
| Decatur, AR | 1,536 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Bokeelia, FL | 1,536 | 36 | 28.0% |
| McCaysville, GA | 1,536 | 1 | 98.0% |
| Limestone, IL | 1,536 | 0 | 100.0% |
| Eagle River, WI | 1,536 | 34 | 32.0% |
| Farwell, TX | 1,535 | 25 | 50.0% |
| Decatur, AR | 1,536 | 44 | 12.0% |
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