| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 38°F | 60°F | 47°F | 2.9" |
| February | 41°F | 64°F | 51°F | 1.6" |
| March | 49°F | 72°F | 60°F | 3.8" |
| April | 57°F | 78°F | 67°F | 3.5" |
| May | 64°F | 84°F | 74°F | 4.4" |
| June | 73°F | 93°F | 82°F | 4.4" |
| July | 76°F | 96°F | 85°F | 1.8" |
| August | 76°F | 98°F | 86°F | 1.6" |
| September | 69°F | 91°F | 79°F | 3.8" |
| October | 58°F | 81°F | 68°F | 4.1" |
| November | 49°F | 70°F | 58°F | 2.7" |
| December | 40°F | 60°F | 49°F | 2.5" |
| Index | Duncanville | Texas | National |
| Air quality index | 51 | 52 | 42 |
| Pollution index | 3,706,540 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 181 |
| Days with moderate air quality | 155 |
| Days w/ poor A.Q. for sensitive groups | 28 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.040% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Highland Park, TX | 9,143 | 51 | 2.0% |
| Midlothian, TX | 31,533 | 51 | 2.0% |
| Arlington, TX | 397,269 | 51 | 2.0% |
| Cedar Hill, TX | 48,337 | 51 | 2.0% |
| Grand Prairie, TX | 193,835 | 51 | 2.0% |
| Duncanville, TX | 39,096 | 51 | 2.0% |
| City | Population | Air Quality Index | National Avg. |
| Norwich, CT | 39,112 | 37 | 26.0% |
| French Valley, CA | 39,057 | 89 | 78.0% |
| South Valley, NM | 39,150 | 53 | 6.0% |
| Germantown, TN | 39,196 | 45 | 10.0% |
| Northglenn, CO | 39,201 | 58 | 16.0% |
| Duncanville, TX | 39,096 | 51 | 2.0% |
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