| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 34°F | 56°F | 44°F | 2.5" |
| February | 38°F | 60°F | 47°F | 2.1" |
| March | 47°F | 69°F | 56°F | 2.9" |
| April | 54°F | 76°F | 64°F | 4.7" |
| May | 61°F | 82°F | 71°F | 5.6" |
| June | 71°F | 91°F | 81°F | 4.5" |
| July | 74°F | 95°F | 84°F | 3.1" |
| August | 74°F | 96°F | 84°F | 3.1" |
| September | 67°F | 89°F | 77°F | 2.9" |
| October | 56°F | 79°F | 66°F | 3.1" |
| November | 46°F | 67°F | 56°F | 2.9" |
| December | 37°F | 56°F | 45°F | 2.6" |
| Index | Bonham | Texas | National |
| Air quality index | 325 | 52 | 42 |
| Pollution index | 723,856 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 138 |
| Days with good air quality | 120 |
| Days with moderate air quality | 17 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Kemp, OK | 254 | 325 | 550.0% |
| Windom, TX | 150 | 325 | 550.0% |
| Trenton, TX | 688 | 325 | 550.0% |
| Dodd City, TX | 505 | 325 | 550.0% |
| Bailey, TX | 296 | 325 | 550.0% |
| Bonham, TX | 10,558 | 325 | 550.0% |
| City | Population | Air Quality Index | National Avg. |
| Independence, OR | 10,559 | 32 | 36.0% |
| Keokuk, IA | 10,556 | 29 | 42.0% |
| Lantana, TX | 10,556 | 51 | 2.0% |
| Bee Ridge, FL | 10,562 | 38 | 24.0% |
| Greencastle, IN | 10,562 | 45 | 10.0% |
| Bonham, TX | 10,558 | 325 | 550.0% |