| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 19°F | 34°F | 26°F | 4.0" |
| February | 20°F | 34°F | 27°F | 4.2" |
| March | 27°F | 44°F | 35°F | 5.1" |
| April | 39°F | 59°F | 48°F | 4.9" |
| May | 48°F | 67°F | 56°F | 4.2" |
| June | 58°F | 75°F | 66°F | 5.3" |
| July | 63°F | 80°F | 71°F | 6.2" |
| August | 62°F | 79°F | 70°F | 3.6" |
| September | 55°F | 72°F | 63°F | 4.3" |
| October | 44°F | 60°F | 51°F | 7.5" |
| November | 35°F | 50°F | 42°F | 5.1" |
| December | 24°F | 37°F | 30°F | 4.7" |
| Index | North Grosvenor Dale | Connecticut | National |
| Air quality index | 40 | 43 | 42 |
| Pollution index | 14,818,200 | 8,629,883 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 312 |
| Days with moderate air quality | 52 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.020% |
| Benzene | 0.150% |
| Carbon Tetrachloride | 0.050% |
| Lead | 0.130% |
| Mercury | 0.040% |
| City | Population | Air Quality Index | National Avg. |
| East Brooklyn, CT | 2,103 | 33 | 34.0% |
| Putnam, CT | 7,138 | 33 | 34.0% |
| South Woodstock, CT | 1,031 | 33 | 34.0% |
| Brooklyn, CT | 1,128 | 33 | 34.0% |
| Danielson, CT | 3,996 | 33 | 34.0% |
| North Grosvenor Dale, CT | 1,180 | 40 | 20.0% |
| City | Population | Air Quality Index | National Avg. |
| Woodbury, GA | 1,180 | 42 | 16.0% |
| Peabody, KS | 1,180 | 40 | 20.0% |
| Lexington, MI | 1,180 | 38 | 24.0% |
| Cottonwood, MN | 1,180 | 32 | 36.0% |
| Tunica, MS | 1,180 | 45 | 10.0% |
| North Grosvenor Dale, CT | 1,180 | 40 | 20.0% |
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