| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 22°F | 37°F | 29°F | 4.2" |
| February | 28°F | 47°F | 36°F | 1.6" |
| March | 34°F | 57°F | 44°F | 2.3" |
| April | 37°F | 64°F | 50°F | 2.0" |
| May | 45°F | 74°F | 59°F | 2.8" |
| June | 52°F | 84°F | 67°F | 1.7" |
| July | 59°F | 94°F | 77°F | 3.8" |
| August | 56°F | 92°F | 73°F | 1.7" |
| September | 48°F | 81°F | 63°F | 3.2" |
| October | 38°F | 66°F | 50°F | 3.2" |
| November | 31°F | 51°F | 39°F | 1.9" |
| December | 22°F | 38°F | 29°F | 2.6" |
| Index | Caldwell | Idaho | National |
| Air quality index | 36 | 32 | 42 |
| Pollution index | 9,401,360 | 2,063,710 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 293 |
| Days with moderate air quality | 60 |
| Days w/ poor A.Q. for sensitive groups | 9 |
| Days with unhealthy air quality | 3 |
| Pollutant | Total |
| Arsenic | 0.060% |
| Benzene | 0.130% |
| Carbon Tetrachloride | 0.090% |
| Lead | 0.070% |
| Mercury | 0.020% |
| City | Population | Air Quality Index | National Avg. |
| Kuna, ID | 20,985 | 36 | 28.0% |
| Nampa, ID | 96,825 | 36 | 28.0% |
| Wilder, ID | 1,740 | 36 | 28.0% |
| Marsing, ID | 1,379 | 36 | 28.0% |
| Notus, ID | 594 | 36 | 28.0% |
| Caldwell, ID | 56,734 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Shoreline, WA | 56,835 | 45 | 10.0% |
| Grand Forks, ND | 56,588 | 33 | 34.0% |
| Welland, ON | 56,929 | n/a | |
| Saint-Hyacinthe, QC | 56,946 | n/a | |
| Palm Beach Gardens, FL | 56,979 | 36 | 28.0% |
| Caldwell, ID | 56,734 | 36 | 28.0% |
Here are the best places to live in Idaho
Check out the 10 most dangerous cities in Idaho
These are the largest cities in Idaho
These are the 10 cheapest cities in Idaho