| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 17°F | 38°F | 26°F | 1.6" |
| February | 20°F | 42°F | 29°F | 1.8" |
| March | 32°F | 57°F | 43°F | 3.6" |
| April | 42°F | 66°F | 53°F | 6.1" |
| May | 52°F | 76°F | 63°F | 6.3" |
| June | 63°F | 86°F | 74°F | 6.4" |
| July | 67°F | 90°F | 78°F | 5.4" |
| August | 64°F | 87°F | 75°F | 7.7" |
| September | 55°F | 80°F | 67°F | 9.2" |
| October | 43°F | 68°F | 54°F | 6.4" |
| November | 31°F | 55°F | 41°F | 4.1" |
| December | 20°F | 40°F | 28°F | 4.1" |
| Index | Firth | Nebraska | National |
| Air quality index | 31 | 86 | 42 |
| Pollution index | 648,221 | 590,627 | 2,726,193 |
| Measurement | Total |
| Days measured | 360 |
| Days with good air quality | 338 |
| Days with moderate air quality | 22 |
| 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 | 0.002% |
| Lead | 0.002% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Cortland, NE | 565 | 31 | 38.0% |
| Douglas, NE | 273 | 31 | 38.0% |
| Bennet, NE | 1,123 | 31 | 38.0% |
| Woodland Hills, NE | 210 | 31 | 38.0% |
| Crab Orchard, NE | 39 | 31 | 38.0% |
| Firth, NE | 440 | 31 | 38.0% |
| City | Population | Air Quality Index | National Avg. |
| Bootjack, CA | 440 | 48 | 4.0% |
| Breda, IA | 440 | 37 | 26.0% |
| Clearfield, IA | 440 | 39 | 22.0% |
| Natoma, KS | 440 | 15 | 70.0% |
| Kingsley, KY | 440 | 49 | 2.0% |
| Firth, NE | 440 | 31 | 38.0% |