| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 48°F | 32°F | 1.2" |
| February | 21°F | 50°F | 34°F | 1.5" |
| March | 30°F | 62°F | 44°F | 1.6" |
| April | 36°F | 66°F | 49°F | 0.2" |
| May | 43°F | 73°F | 57°F | 2.4" |
| June | 54°F | 89°F | 71°F | 1.1" |
| July | 59°F | 92°F | 75°F | 2.1" |
| August | 56°F | 90°F | 72°F | 1.1" |
| September | 49°F | 82°F | 64°F | 0.2" |
| October | 38°F | 69°F | 52°F | 2.1" |
| November | 28°F | 58°F | 41°F | 2.6" |
| December | 17°F | 46°F | 30°F | 0.7" |
| Index | Boulder | Colorado | National |
| Air quality index | 47 | 38 | 42 |
| Pollution index | 1,028,850 | 2,068,342 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 227 |
| Days with moderate air quality | 133 |
| Days w/ poor A.Q. for sensitive groups | 5 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.240% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Mead, CO | 4,978 | 45 | 10.0% |
| Coal Creek, CO | 2,605 | 47 | 6.0% |
| Louisville, CO | 19,342 | 47 | 6.0% |
| Broomfield, CO | 69,444 | 47 | 6.0% |
| Superior, CO | 13,292 | 47 | 6.0% |
| Boulder, CO | 108,777 | 47 | 6.0% |
| City | Population | Air Quality Index | National Avg. |
| Broken Arrow, OK | 108,875 | 45 | 10.0% |
| San Buenaventura (Ventura), CA | 108,467 | 46 | 8.0% |
| Inglewood, CA | 109,309 | 72 | 44.0% |
| Sandy Springs, GA | 108,180 | 52 | 4.0% |
| Hillsboro, OR | 108,026 | 38 | 24.0% |
| Boulder, CO | 108,777 | 47 | 6.0% |
Here are the best places to live in Colorado
These are the 10 cheapest cities in Colorado
Most Dangerous Cities In The US
See the best places to live in Boulder