| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 42°F | 65°F | 52°F | 3.0" |
| February | 46°F | 69°F | 56°F | 1.5" |
| March | 53°F | 76°F | 63°F | 4.0" |
| April | 60°F | 82°F | 70°F | 2.9" |
| May | 66°F | 88°F | 76°F | 5.9" |
| June | 73°F | 95°F | 83°F | 3.4" |
| July | 75°F | 97°F | 85°F | 3.0" |
| August | 76°F | 99°F | 86°F | 2.2" |
| September | 71°F | 93°F | 80°F | 4.5" |
| October | 61°F | 84°F | 71°F | 3.9" |
| November | 52°F | 74°F | 62°F | 2.4" |
| December | 44°F | 65°F | 53°F | 2.5" |
| Index | Wells Branch | Texas | National |
| Air quality index | 44 | 52 | 42 |
| Pollution index | 1,922,400 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 249 |
| Days with moderate air quality | 114 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.010% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Hornsby Bend, TX | 8,860 | 44 | 12.0% |
| West Lake Hills, TX | 3,420 | 44 | 12.0% |
| Hudson Bend, TX | 2,525 | 44 | 12.0% |
| Pflugerville, TX | 65,733 | 44 | 12.0% |
| Lost Creek, TX | 1,160 | 44 | 12.0% |
| Wells Branch, TX | 12,950 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Bonita, CA | 12,952 | 64 | 28.0% |
| Echelon, NJ | 12,954 | 51 | 2.0% |
| Justice, IL | 12,945 | 55 | 10.0% |
| Endicott, NY | 12,939 | 36 | 28.0% |
| Kewanee, IL | 12,961 | 41 | 18.0% |
| Wells Branch, TX | 12,950 | 44 | 12.0% |