| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 35°F | 50°F | 43°F | 11.1" |
| February | 38°F | 54°F | 46°F | 7.1" |
| March | 46°F | 65°F | 56°F | 6.7" |
| April | 54°F | 74°F | 65°F | 10.2" |
| May | 62°F | 81°F | 72°F | 7.9" |
| June | 71°F | 89°F | 81°F | 4.8" |
| July | 73°F | 90°F | 82°F | 5.6" |
| August | 72°F | 90°F | 82°F | 7.4" |
| September | 65°F | 84°F | 75°F | 33.9" |
| October | 54°F | 74°F | 64°F | 26.5" |
| November | 44°F | 63°F | 54°F | 11.0" |
| December | 39°F | 55°F | 47°F | 12.3" |
| Index | Decherd | Tennessee | National |
| Air quality index | 46 | 76 | 42 |
| Pollution index | 303,917 | 2,454,916 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 230 |
| Days with moderate air quality | 135 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Tullahoma, TN | 20,737 | 31 | 38.0% |
| Estill Springs, TN | 2,144 | 44 | 12.0% |
| Huntland, TN | 1,095 | 44 | 12.0% |
| Winchester, TN | 9,014 | 44 | 12.0% |
| Hillsboro, TN | 348 | 46 | 8.0% |
| Decherd, TN | 2,932 | 46 | 8.0% |
| City | Population | Air Quality Index | National Avg. |
| Harrisburg, AR | 2,931 | 45 | 10.0% |
| Somerset, WI | 2,931 | 46 | 8.0% |
| Saint-André-d'Argenteuil, QC | 2,931 | n/a | |
| David City, NE | 2,933 | 31 | 38.0% |
| Saint-Marc-des-Carrières, QC | 2,933 | n/a | |
| Decherd, TN | 2,932 | 46 | 8.0% |