| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 43°F | 64°F | 52°F | 2.4" |
| February | 47°F | 69°F | 56°F | 2.1" |
| March | 54°F | 75°F | 63°F | 3.7" |
| April | 61°F | 81°F | 70°F | 4.7" |
| May | 67°F | 87°F | 76°F | 6.0" |
| June | 74°F | 93°F | 83°F | 2.9" |
| July | 75°F | 95°F | 84°F | 2.1" |
| August | 75°F | 97°F | 85°F | 5.4" |
| September | 71°F | 91°F | 79°F | 3.7" |
| October | 61°F | 84°F | 71°F | 2.7" |
| November | 53°F | 74°F | 62°F | 2.7" |
| December | 46°F | 66°F | 54°F | 1.9" |
| Index | Smithville | Texas | National |
| Air quality index | 44 | 52 | 42 |
| Pollution index | 1,591,270 | 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 | 0.030% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.010% |
| Mercury | 0.360% |
| City | Population | Air Quality Index | National Avg. |
| Bastrop, TX | 9,094 | 44 | 12.0% |
| Camp Swift, TX | 6,529 | 44 | 12.0% |
| Circle D-KC Estates, TX | 2,761 | 44 | 12.0% |
| Giddings, TX | 5,095 | 44 | 12.0% |
| Smithville, TX | 4,501 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| New Roads, LA | 4,500 | 45 | 10.0% |
| Louisburg, KS | 4,499 | 47 | 6.0% |
| Royal Pines, NC | 4,499 | 44 | 12.0% |
| Heeia, HI | 4,503 | 30 | 40.0% |
| Jonesboro, LA | 4,503 | 34 | 32.0% |
| Smithville, TX | 4,501 | 44 | 12.0% |
Here are the best places to live in Texas
See the best places to live in Smithville
These are the largest cities in Texas
These are the 10 cheapest cities in Texas