| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 40°F | 65°F | 52°F | 2.5" |
| February | 45°F | 70°F | 56°F | 1.3" |
| March | 51°F | 77°F | 63°F | 2.8" |
| April | 58°F | 83°F | 70°F | 2.4" |
| May | 65°F | 88°F | 76°F | 4.2" |
| June | 72°F | 95°F | 82°F | 2.2" |
| July | 73°F | 96°F | 83°F | 3.3" |
| August | 73°F | 98°F | 85°F | 2.2" |
| September | 69°F | 93°F | 79°F | 4.1" |
| October | 59°F | 85°F | 71°F | 2.5" |
| November | 51°F | 75°F | 62°F | 1.7" |
| December | 43°F | 66°F | 53°F | 2.1" |
| Index | Seguin | Texas | National |
| Air quality index | 49 | 52 | 42 |
| Pollution index | 24,182,700 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 196 |
| Days with moderate air quality | 163 |
| Days w/ poor A.Q. for sensitive groups | 5 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.310% |
| Benzene | 0.310% |
| Carbon Tetrachloride | 0.080% |
| Lead | 0.140% |
| Mercury | 0.230% |
| City | Population | Air Quality Index | National Avg. |
| Staples, TX | 180 | 44 | 12.0% |
| Kingsbury, TX | 191 | 49 | 2.0% |
| St. Hedwig, TX | 2,474 | 49 | 2.0% |
| Zuehl, TX | 515 | 49 | 2.0% |
| Lake Dunlap, TX | 1,546 | 49 | 2.0% |
| Seguin, TX | 29,458 | 49 | 2.0% |
| City | Population | Air Quality Index | National Avg. |
| Suisun City, CA | 29,459 | 35 | 30.0% |
| Canton, GA | 29,459 | 52 | 4.0% |
| Austintown, OH | 29,467 | 42 | 16.0% |
| East Palo Alto, CA | 29,448 | 43 | 14.0% |
| Stockbridge, GA | 29,446 | 52 | 4.0% |
| Seguin, TX | 29,458 | 49 | 2.0% |
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