| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 29°F | 48°F | 37°F | 14.0" |
| February | 33°F | 54°F | 41°F | 4.0" |
| March | 44°F | 66°F | 53°F | 2.2" |
| April | 46°F | 69°F | 56°F | 6.4" |
| May | 57°F | 79°F | 66°F | 6.4" |
| June | 65°F | 86°F | 74°F | 8.7" |
| July | 67°F | 89°F | 77°F | 10.0" |
| August | 70°F | 92°F | 79°F | 12.5" |
| September | 63°F | 86°F | 73°F | 10.7" |
| October | 49°F | 74°F | 60°F | 6.1" |
| November | 41°F | 64°F | 50°F | 31.2" |
| December | 29°F | 51°F | 38°F | 4.9" |
| Index | Dennis | Oklahoma | National |
| Air quality index | 38 | 55 | 42 |
| Pollution index | 1,549,330 | 1,271,533 | 2,726,193 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 289 |
| Days with moderate air quality | 73 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.230% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.070% |
| Mercury | 0.210% |
| City | Population | Air Quality Index | National Avg. |
| Old Eucha, OK | 31 | 36 | 28.0% |
| Hoot Owl, OK | 0 | 36 | 28.0% |
| Kenwood, OK | 1,017 | 36 | 28.0% |
| Spavinaw, OK | 426 | 36 | 28.0% |
| Tagg Flats, OK | 0 | 36 | 28.0% |
| Dennis, OK | 91 | 38 | 24.0% |
| City | Population | Air Quality Index | National Avg. |
| Lowell Point, AK | 91 | 31 | 38.0% |
| Guion, AR | 91 | 36 | 28.0% |
| Hat Creek, CA | 91 | 42 | 16.0% |
| Lake Davis, CA | 91 | 44 | 12.0% |
| Peoria, CO | 91 | 58 | 16.0% |
| Dennis, OK | 91 | 38 | 24.0% |
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