| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 38°F | 28°F | 5.1" |
| February | 20°F | 40°F | 29°F | 3.4" |
| March | 29°F | 50°F | 38°F | 3.8" |
| April | 39°F | 64°F | 51°F | 4.0" |
| May | 49°F | 73°F | 61°F | 4.1" |
| June | 58°F | 80°F | 68°F | 5.3" |
| July | 63°F | 85°F | 73°F | 6.2" |
| August | 60°F | 82°F | 70°F | 5.8" |
| September | 54°F | 76°F | 64°F | 4.5" |
| October | 43°F | 65°F | 53°F | 4.8" |
| November | 33°F | 53°F | 43°F | 2.9" |
| December | 27°F | 43°F | 34°F | 4.8" |
| Index | Mountain Lake | New Jersey | National |
| Air quality index | 34 | 45 | 42 |
| Pollution index | 2,789,290 | 7,246,891 | 2,726,193 |
| Measurement | Total |
| Days measured | 349 |
| Days with good air quality | 340 |
| Days with moderate air quality | 9 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.020% |
| Mercury | 0.030% |
| City | Population | Air Quality Index | National Avg. |
| Pen Argyl, PA | 3,551 | 34 | 32.0% |
| Brass Castle, NJ | 1,629 | 34 | 32.0% |
| Martins Creek, PA | 457 | 34 | 32.0% |
| Newton, NJ | 7,935 | 34 | 32.0% |
| Annandale, NJ | 1,794 | 34 | 32.0% |
| Mountain Lake, NJ | 565 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Carnelian Bay, CA | 565 | 44 | 12.0% |
| Mountain View, CO | 565 | 58 | 16.0% |
| German Valley, IL | 565 | 42 | 16.0% |
| Etna Green, IN | 565 | 37 | 26.0% |
| Richmond, LA | 565 | 34 | 32.0% |
| Mountain Lake, NJ | 565 | 34 | 32.0% |
Here are the best places to live in New Jersey
Most Dangerous States In The US
Safest States In The US
These are the 10 cheapest cities in New Jersey