| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 14°F | 35°F | 23°F | 1.0" |
| February | 20°F | 43°F | 30°F | 0.8" |
| March | 32°F | 61°F | 45°F | 6.5" |
| April | 38°F | 64°F | 50°F | 8.3" |
| May | 49°F | 77°F | 62°F | 2.9" |
| June | 59°F | 84°F | 71°F | 6.5" |
| July | 65°F | 93°F | 78°F | 8.4" |
| August | 64°F | 91°F | 76°F | 5.0" |
| September | 56°F | 86°F | 69°F | 2.1" |
| October | 42°F | 71°F | 55°F | 4.7" |
| November | 27°F | 59°F | 41°F | 3.1" |
| December | 15°F | 38°F | 25°F | 1.3" |
| Index | Herndon | Kansas | National |
| Air quality index | 19 | 47 | 42 |
| Pollution index | 252,184 | 989,153 | 2,726,193 |
| Measurement | Total |
| Days measured | 60 |
| Days with good air quality | 55 |
| Days with moderate air quality | 5 |
| Days w/ poor A.Q. for sensitive groups | |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.000% |
| Benzene | 0.004% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Atwood, KS | 1,186 | 19 | 62.0% |
| Oberlin, KS | 1,771 | 19 | 62.0% |
| Herndon, KS | 153 | 19 | 62.0% |
| City | Population | Air Quality Index | National Avg. |
| Port Graham, AK | 153 | 31 | 38.0% |
| Day, FL | 153 | 38 | 24.0% |
| Palmer, IA | 153 | 37 | 26.0% |
| Rutland, IA | 153 | 37 | 26.0% |
| Salamonia, IN | 153 | 35 | 30.0% |
| Herndon, KS | 153 | 19 | 62.0% |