| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 34°F | 26°F | 2.0" |
| February | 28°F | 48°F | 37°F | 1.2" |
| March | 36°F | 58°F | 45°F | 7.3" |
| April | 45°F | 66°F | 54°F | 7.1" |
| May | 53°F | 75°F | 63°F | 8.1" |
| June | 65°F | 87°F | 76°F | 8.2" |
| July | 67°F | 87°F | 76°F | 6.8" |
| August | 63°F | 83°F | 72°F | 7.2" |
| September | 60°F | 82°F | 70°F | 7.1" |
| October | 46°F | 69°F | 57°F | 6.0" |
| November | 35°F | 56°F | 45°F | 2.4" |
| December | 23°F | 40°F | 30°F | 6.3" |
| Index | Randolph | Iowa | National |
| Air quality index | 40 | 39 | 50 |
| Pollution index | 747,023 | 1,643,836 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 283 |
| Days with moderate air quality | 82 |
| 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 | 0.050% |
| Mercury | 0.030% |
| City, State | Population | Air Quality Index | National Avg. |
| Percival, IA | 102 | 40 | 20% |
| Anderson, IA | 0 | 40 | 20% |
| Tabor, IA | 1,230 | 40 | 20% |
| Hastings, IA | 150 | 40 | 20% |
| Riverton, IA | 260 | 40 | 20% |
| Randolph, IA | 190 | 40 | 20% |
| City, State | Population | Air Quality Index | National Avg. |
| Manitou, OK | 190 | 43 | 14% |
| Baylis, IL | 190 | 41 | 18% |
| Watson, MN | 190 | 32 | 36% |
| Clipper Mills, CA | 190 | 44 | 12% |
| Parkdale, MO | 190 | 54 | 8% |
| Randolph, IA | 190 | 40 | 20% |
Here are the best places to live in Iowa
10 Best cities in Iowa for employment
See the best places to live in & around Randolph
Check out the 10 safest cities in Iowa