| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | -2°F | 35°F | 15°F | 0.4" |
| February | 6°F | 43°F | 24°F | 0.3" |
| March | 17°F | 56°F | 36°F | 0.6" |
| April | 24°F | 63°F | 44°F | 0.7" |
| May | 32°F | 71°F | 52°F | 0.7" |
| June | 40°F | 83°F | 63°F | 0.3" |
| July | 47°F | 85°F | 66°F | 1.4" |
| August | 44°F | 82°F | 63°F | 1.1" |
| September | 36°F | 77°F | 56°F | 1.1" |
| October | 25°F | 66°F | 44°F | 0.8" |
| November | 12°F | 53°F | 31°F | 0.5" |
| December | 0°F | 38°F | 18°F | 0.5" |
| Index | Costilla | New Mexico | National |
| Air quality index | 15 | 37 | 42 |
| Pollution index | 292,539 | 2,051,791 | 2,726,193 |
| Measurement | Total |
| Days measured | 358 |
| Days with good air quality | 334 |
| Days with moderate air quality | 24 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Costilla, NM | 91 | 15 | 70.0% |
| City | Population | Air Quality Index | National Avg. |
| Beaver, AK | 91 | 38 | 24.0% |
| Nondalton, AK | 91 | 31 | 38.0% |
| Cokedale, CO | 91 | 15 | 70.0% |
| Reubens, ID | 91 | 29 | 42.0% |
| Tennessee, IL | 91 | 29 | 42.0% |
| Costilla, NM | 91 | 15 | 70.0% |