| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 42°F | 63°F | 52°F | 2.4" |
| February | 46°F | 67°F | 55°F | 2.9" |
| March | 53°F | 74°F | 62°F | 3.6" |
| April | 60°F | 80°F | 69°F | 2.5" |
| May | 67°F | 86°F | 75°F | 5.1" |
| June | 73°F | 93°F | 82°F | 2.7" |
| July | 75°F | 94°F | 83°F | 1.7" |
| August | 75°F | 96°F | 84°F | 4.8" |
| September | 70°F | 90°F | 79°F | 2.9" |
| October | 60°F | 83°F | 70°F | 2.7" |
| November | 52°F | 73°F | 61°F | 3.1" |
| December | 46°F | 65°F | 54°F | 3.1" |
| Index | Brenham | Texas | National |
| Air quality index | 52 | 52 | 42 |
| Pollution index | 898,232 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 171 |
| Days with moderate air quality | 163 |
| Days w/ poor A.Q. for sensitive groups | 26 |
| Days with unhealthy air quality | 4 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.004% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Burton, TX | 318 | 44 | 12.0% |
| Somerville, TX | 1,254 | 44 | 12.0% |
| Bellville, TX | 4,318 | 52 | 4.0% |
| Industry, TX | 286 | 52 | 4.0% |
| Brenham, TX | 17,717 | 52 | 4.0% |
| City | Population | Air Quality Index | National Avg. |
| Pinewood, FL | 17,714 | 41 | 18.0% |
| Estelle, LA | 17,706 | 45 | 10.0% |
| Sevierville, TN | 17,729 | 44 | 12.0% |
| Pampa, TX | 17,743 | 44 | 12.0% |
| Nederland, TX | 17,748 | 45 | 10.0% |
| Brenham, TX | 17,717 | 52 | 4.0% |