| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 40°F | 32°F | 2.6" |
| February | 23°F | 41°F | 32°F | 2.8" |
| March | 30°F | 48°F | 39°F | 3.4" |
| April | 40°F | 60°F | 50°F | 4.5" |
| May | 50°F | 69°F | 59°F | 3.8" |
| June | 60°F | 78°F | 68°F | 4.7" |
| July | 66°F | 84°F | 75°F | 3.1" |
| August | 64°F | 82°F | 74°F | 3.7" |
| September | 58°F | 77°F | 67°F | 3.2" |
| October | 47°F | 66°F | 57°F | 4.5" |
| November | 37°F | 55°F | 46°F | 2.9" |
| December | 30°F | 45°F | 37°F | 4.2" |
| Index | East Rock | New Haven | Connecticut |
| Air quality index | 41 | 41 | 43 |
| Pollution index | 14,500,300 | 14,500,300 | 8,629,883 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 280 |
| Days with moderate air quality | 71 |
| Days w/ poor A.Q. for sensitive groups | 12 |
| Days with unhealthy air quality | 2 |
| Pollutant | Total |
| Arsenic | 0.030% |
| Benzene | 0.140% |
| Carbon Tetrachloride | 0.050% |
| Lead | 0.080% |
| Mercury | 0.060% |
| City | Population | Air Quality Index | National Avg. |
| Durham, CT | 3,542 | 41 | 18.0% |
| Derby, CT | 12,420 | 41 | 18.0% |
| East Haven, CT | 28,645 | 41 | 18.0% |
| Woodmont, CT | 1,601 | 41 | 18.0% |
| Naugatuck, CT | 31,201 | 41 | 18.0% |
| New Haven, CT | 130,381 | 41 | 18.0% |
| City | Population | Air Quality Index | National Avg. |
| Stamford, CT | 130,057 | 43 | 14.0% |
| Kent, WA | 130,038 | 45 | 10.0% |
| Concord, CA | 129,227 | 40 | 20.0% |
| Round Rock, TX | 128,812 | 44 | 12.0% |
| Langley, BC | 132,088 | n/a | |
| New Haven, CT | 130,381 | 41 | 18.0% |
Here are the best places to live in Connecticut
Check out the 10 safest cities in Connecticut
See the best places to live in New Haven
Most Dangerous States In The US