| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 42°F | 65°F | 52°F | 3.2" |
| February | 46°F | 69°F | 56°F | 2.4" |
| March | 53°F | 75°F | 63°F | 3.6" |
| April | 60°F | 81°F | 70°F | 4.6" |
| May | 66°F | 86°F | 76°F | 5.4" |
| June | 73°F | 93°F | 82°F | 4.5" |
| July | 74°F | 94°F | 83°F | 4.5" |
| August | 74°F | 95°F | 84°F | 6.2" |
| September | 70°F | 91°F | 79°F | 3.3" |
| October | 59°F | 83°F | 70°F | 5.2" |
| November | 51°F | 74°F | 61°F | 3.4" |
| December | 45°F | 66°F | 54°F | 3.0" |
| Index | Tomball | Texas | National |
| Air quality index | 52 | 52 | 42 |
| Pollution index | 70,353,000 | 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 | 0.210% |
| Benzene | 0.560% |
| Carbon Tetrachloride | 5.850% |
| Lead | 0.690% |
| Mercury | 0.960% |
| City | Population | Air Quality Index | National Avg. |
| Oak Ridge North, TX | 3,262 | 52 | 4.0% |
| Woodloch, TX | 121 | 52 | 4.0% |
| Pinehurst city, TX | 2,145 | 52 | 4.0% |
| Todd Mission, TX | 126 | 52 | 4.0% |
| Shenandoah, TX | 3,060 | 52 | 4.0% |
| Tomball, TX | 11,992 | 52 | 4.0% |
| City | Population | Air Quality Index | National Avg. |
| Shiloh, OH | 11,996 | 41 | 18.0% |
| Wetaskiwin County No. 10, AB | 11,985 | n/a | |
| Elk City, OK | 11,999 | 43 | 14.0% |
| View Park-Windsor Hills, CA | 12,000 | 72 | 44.0% |
| Norwich, ON | 12,006 | n/a | |
| Tomball, TX | 11,992 | 52 | 4.0% |