Harmony, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.1 °C (low) to 16.6 °C (high). Annual precipitation averages 1287.8 Millimeters. Harmony is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.7 °C | 3.1 °C | 89.92 mm |
| February | -6 °C | 4.7 °C | 73.66 mm |
| March | -2.1 °C | 9.3 °C | 100.84 mm |
| April | 3.8 °C | 16.3 °C | 101.35 mm |
| May | 9.4 °C | 21.8 °C | 107.44 mm |
| June | 14.4 °C | 26.6 °C | 123.7 mm |
| July | 17.1 °C | 29.2 °C | 123.19 mm |
| August | 16.2 °C | 28.1 °C | 125.22 mm |
| September | 12.2 °C | 24.5 °C | 123.44 mm |
| October | 5.9 °C | 18.1 °C | 118.62 mm |
| November | 0.2 °C | 11.8 °C | 89.41 mm |
| December | -3.7 °C | 5.9 °C | 111 mm |
| Annual | 5.1 °C | 16.6 °C | 1287.79 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |