| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 39°F | 58°F | 47°F | 7.1" |
| February | 42°F | 62°F | 51°F | 2.6" |
| March | 51°F | 70°F | 60°F | 7.1" |
| April | 58°F | 77°F | 67°F | 9.9" |
| May | 66°F | 84°F | 74°F | 11.4" |
| June | 75°F | 92°F | 83°F | 5.8" |
| July | 77°F | 95°F | 86°F | 2.0" |
| August | 78°F | 96°F | 87°F | 1.4" |
| September | 71°F | 89°F | 80°F | 0.5" |
| October | 60°F | 79°F | 69°F | 14.4" |
| November | 50°F | 68°F | 58°F | 8.2" |
| December | 40°F | 58°F | 48°F | 6.1" |
| Index | Plano | Texas | National |
| Air quality index | 51 | 52 | 42 |
| Pollution index | 8,884,190 | 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 | 0.030% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.040% |
| Lead | 0.260% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Highland Park, TX | 9,143 | 51 | 2.0% |
| University Park, TX | 25,027 | 51 | 2.0% |
| Murphy, TX | 20,711 | 51 | 2.0% |
| Sachse, TX | 25,888 | 51 | 2.0% |
| Fairview, TX | 8,998 | 51 | 2.0% |
| Plano, TX | 288,870 | 51 | 2.0% |
| City | Population | Air Quality Index | National Avg. |
| Lincoln, NE | 286,388 | 31 | 38.0% |
| Anchorage, AK | 292,090 | 31 | 38.0% |
| Orlando, FL | 284,817 | 39 | 22.0% |
| Gatineau, QC | 293,695 | n/a | |
| Greensboro, NC | 294,395 | 43 | 14.0% |
| Plano, TX | 288,870 | 51 | 2.0% |
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