| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 22°F | 38°F | 29°F | 6.3" |
| February | 20°F | 38°F | 29°F | 6.1" |
| March | 28°F | 47°F | 37°F | 8.2" |
| April | 39°F | 59°F | 48°F | 7.7" |
| May | 48°F | 69°F | 58°F | 6.4" |
| June | 56°F | 76°F | 65°F | 7.2" |
| July | 63°F | 82°F | 72°F | 10.6" |
| August | 60°F | 80°F | 69°F | 9.0" |
| September | 54°F | 73°F | 63°F | 8.3" |
| October | 44°F | 63°F | 53°F | 7.9" |
| November | 35°F | 52°F | 43°F | 8.0" |
| December | 27°F | 42°F | 34°F | 7.8" |
| Index | Harrisville | Rhode Island | National |
| Air quality index | 44 | 45 | 42 |
| Pollution index | 8,312,000 | 3,440,259 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 289 |
| Days with moderate air quality | 74 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.090% |
| Carbon Tetrachloride | 0.040% |
| Lead | 0.210% |
| Mercury | 0.060% |
| City | Population | Air Quality Index | National Avg. |
| Wauregan, CT | 1,486 | 33 | 34.0% |
| Brooklyn, CT | 1,128 | 33 | 34.0% |
| Putnam, CT | 7,138 | 33 | 34.0% |
| Danielson, CT | 3,996 | 33 | 34.0% |
| South Woodstock, CT | 1,031 | 33 | 34.0% |
| Harrisville, RI | 1,284 | 44 | 12.0% |
| City | Population | Air Quality Index | National Avg. |
| Marshallville, GA | 1,284 | 38 | 24.0% |
| Pine Knoll Shores, NC | 1,284 | 37 | 26.0% |
| Addison (Webster Springs), WV | 1,284 | 31 | 38.0% |
| Barrackville, WV | 1,284 | 31 | 38.0% |
| Hudson Lake, IN | 1,285 | 42 | 16.0% |
| Harrisville, RI | 1,284 | 44 | 12.0% |
Here are the best places to live in Rhode Island
See the best places to live in Harrisville
Check out the 10 safest cities in Rhode Island
These are the 10 cheapest cities in Rhode Island