| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 38°F | 28°F | 3.3" |
| February | 18°F | 40°F | 29°F | 3.6" |
| March | 26°F | 50°F | 38°F | 3.6" |
| April | 37°F | 65°F | 50°F | 4.0" |
| May | 47°F | 75°F | 60°F | 4.0" |
| June | 57°F | 82°F | 69°F | 5.5" |
| July | 63°F | 88°F | 75°F | 4.9" |
| August | 60°F | 86°F | 72°F | 4.9" |
| September | 54°F | 80°F | 66°F | 3.9" |
| October | 43°F | 67°F | 54°F | 5.9" |
| November | 32°F | 55°F | 43°F | 3.2" |
| December | 24°F | 44°F | 33°F | 4.5" |
| Index | Norfolk | Connecticut | National |
| Air quality index | 37 | 43 | 42 |
| Pollution index | 7,859,360 | 8,629,883 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 342 |
| Days with moderate air quality | 23 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.030% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.030% |
| Lead | 0.320% |
| Mercury | 0.070% |
| City | Population | Air Quality Index | National Avg. |
| Sharon, CT | 635 | 37 | 26.0% |
| Lakeville, CT | 830 | 37 | 26.0% |
| Great Barrington, MA | 2,213 | 37 | 26.0% |
| Winsted, CT | 6,504 | 37 | 26.0% |
| Northwest Harwinton, CT | 2,897 | 37 | 26.0% |
| Norfolk, CT | 639 | 37 | 26.0% |
| City | Population | Air Quality Index | National Avg. |
| Swea City, IA | 639 | 15 | 70.0% |
| Apple Canyon Lake, IL | 639 | 29 | 42.0% |
| New Market, IN | 639 | 42 | 16.0% |
| Sicily Island, LA | 639 | 34 | 32.0% |
| Battle Lake, MN | 639 | 33 | 34.0% |
| Norfolk, CT | 639 | 37 | 26.0% |
Here are the best places to live in Connecticut
Check out the 10 most dangerous cities in Connecticut
Most Dangerous Cities In The US
These are the largest cities in Connecticut