| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 32°F | 54°F | 41°F | 6.2" |
| February | 35°F | 57°F | 44°F | 12.1" |
| March | 45°F | 68°F | 55°F | 7.8" |
| April | 52°F | 75°F | 62°F | 11.9" |
| May | 61°F | 81°F | 70°F | 7.2" |
| June | 70°F | 90°F | 80°F | 12.0" |
| July | 73°F | 94°F | 83°F | 17.8" |
| August | 73°F | 94°F | 82°F | 8.2" |
| September | 64°F | 87°F | 74°F | 7.7" |
| October | 54°F | 77°F | 64°F | 13.4" |
| November | 44°F | 66°F | 53°F | 2.7" |
| December | 34°F | 53°F | 42°F | 2.7" |
| Index | Cromwell | Oklahoma | National |
| Air quality index | 36 | 55 | 42 |
| Pollution index | 918,837 | 1,271,533 | 2,726,193 |
| Measurement | Total |
| Days measured | 231 |
| Days with good air quality | 216 |
| Days with moderate air quality | 14 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.010% |
| Mercury | 0.005% |
| City | Population | Air Quality Index | National Avg. |
| Bowlegs, OK | 406 | 36 | 28.0% |
| IXL, OK | 43 | 36 | 28.0% |
| Okemah, OK | 3,275 | 36 | 28.0% |
| Lima, OK | 61 | 36 | 28.0% |
| Bearden, OK | 142 | 36 | 28.0% |
| Cromwell, OK | 307 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Caspar, CA | 307 | 33 | 34.0% |
| Oak Glen, CA | 307 | 89 | 78.0% |
| Kinderhook, IL | 307 | 41 | 18.0% |
| Glenwood, IN | 307 | 28 | 44.0% |
| Switz City, IN | 307 | 1 | 98.0% |
| Cromwell, OK | 307 | 36 | 28.0% |
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