| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 46°F | 32°F | 7.4" |
| February | 25°F | 48°F | 35°F | 1.8" |
| March | 35°F | 61°F | 46°F | 11.2" |
| April | 44°F | 69°F | 55°F | 9.9" |
| May | 53°F | 77°F | 64°F | 6.6" |
| June | 64°F | 89°F | 76°F | 5.0" |
| July | 68°F | 93°F | 80°F | 5.5" |
| August | 66°F | 90°F | 77°F | 8.1" |
| September | 59°F | 83°F | 69°F | 8.3" |
| October | 46°F | 71°F | 57°F | 4.5" |
| November | 34°F | 59°F | 45°F | 2.8" |
| December | 24°F | 45°F | 33°F | 4.9" |
| Index | St. John | Kansas | National |
| Air quality index | 15 | 47 | 42 |
| Pollution index | 231,146 | 989,153 | 2,726,193 |
| Measurement | Total |
| Days measured | 304 |
| Days with good air quality | 301 |
| Days with moderate air quality | 3 |
| 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. |
| Radium, KS | 7 | 15 | 70.0% |
| Seward, KS | 63 | 15 | 70.0% |
| Byers, KS | 22 | 15 | 70.0% |
| Macksville, KS | 570 | 15 | 70.0% |
| Stafford, KS | 830 | 40 | 20.0% |
| St. John, KS | 1,377 | 15 | 70.0% |
| City | Population | Air Quality Index | National Avg. |
| Marmaduke, AR | 1,377 | 26 | 48.0% |
| Jonesville, LA | 1,377 | 30 | 40.0% |
| Bourne, MA | 1,377 | 36 | 28.0% |
| Beggs, OK | 1,377 | 45 | 10.0% |
| Factoryville, PA | 1,377 | 38 | 24.0% |
| St. John, KS | 1,377 | 15 | 70.0% |
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