| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 25°F | 42°F | 33°F | 3.3" |
| February | 25°F | 43°F | 34°F | 2.4" |
| March | 33°F | 53°F | 42°F | 3.4" |
| April | 43°F | 66°F | 54°F | 3.8" |
| May | 52°F | 75°F | 63°F | 3.9" |
| June | 62°F | 83°F | 72°F | 5.3" |
| July | 67°F | 88°F | 77°F | 5.1" |
| August | 65°F | 85°F | 75°F | 4.7" |
| September | 59°F | 79°F | 68°F | 3.5" |
| October | 48°F | 68°F | 57°F | 4.2" |
| November | 37°F | 57°F | 46°F | 2.9" |
| December | 31°F | 47°F | 38°F | 4.3" |
| Index | Hopewell | New Jersey | National |
| Air quality index | 41 | 45 | 42 |
| Pollution index | 3,313,920 | 7,246,891 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 280 |
| Days with moderate air quality | 83 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.350% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.004% |
| Lead | 0.350% |
| Mercury | 0.340% |
| City | Population | Air Quality Index | National Avg. |
| Blawenburg, NJ | 99 | 41 | 18.0% |
| Franklin Park, NJ | 12,738 | 41 | 18.0% |
| Kendall Park, NJ | 9,852 | 41 | 18.0% |
| Pleasant Plains, NJ | 627 | 41 | 18.0% |
| Skillman, NJ | 476 | 41 | 18.0% |
| Hopewell, NJ | 1,857 | 41 | 18.0% |
| City | Population | Air Quality Index | National Avg. |
| San Augustine, TX | 1,857 | 39 | 22.0% |
| Waterbury, VT | 1,857 | 37 | 26.0% |
| Fairlea, WV | 1,857 | 41 | 18.0% |
| Notre-Dame-des-Pins, QC | 1,857 | n/a | |
| Fraser Valley D, BC | 1,857 | n/a | |
| Hopewell, NJ | 1,857 | 41 | 18.0% |
Here are the best places to live in New Jersey
Check out the 10 most dangerous cities in New Jersey
Check out the 10 safest cities in New Jersey
Safest States In The US