Harrison, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 8.2 °C (low) to 17.6 °C (high). Annual precipitation averages 1220.7 Millimeters. Harrison is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.8 °C | 4.4 °C | 90.68 mm |
| February | -2.9 °C | 5.9 °C | 72.64 mm |
| March | 0.8 °C | 10.2 °C | 108.71 mm |
| April | 6.5 °C | 16.7 °C | 102.62 mm |
| May | 11.9 °C | 22.3 °C | 101.85 mm |
| June | 17.2 °C | 27.4 °C | 113.54 mm |
| July | 20.4 °C | 30.2 °C | 113.79 mm |
| August | 19.6 °C | 29.2 °C | 112.01 mm |
| September | 15.8 °C | 25.6 °C | 104.9 mm |
| October | 9.2 °C | 18.9 °C | 108.46 mm |
| November | 3.7 °C | 12.8 °C | 87.63 mm |
| December | -0.5 °C | 7.3 °C | 103.89 mm |
| Annual | 8.2 °C | 17.6 °C | 1220.72 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |