Grenloch, New Jersey has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.9 °C (low) to 18.3 °C (high). Annual precipitation averages 1200.7 Millimeters. Grenloch 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 | -3.7 °C | 5.3 °C | 94.23 mm |
| February | -2.9 °C | 6.8 °C | 71.63 mm |
| March | 0.8 °C | 11.1 °C | 115.06 mm |
| April | 6.4 °C | 17.8 °C | 89.66 mm |
| May | 11.6 °C | 23.2 °C | 96.01 mm |
| June | 16.9 °C | 28.3 °C | 108.46 mm |
| July | 20 °C | 30.7 °C | 118.11 mm |
| August | 19 °C | 29.6 °C | 117.86 mm |
| September | 15.4 °C | 25.8 °C | 104.14 mm |
| October | 8.6 °C | 19.2 °C | 99.57 mm |
| November | 3 °C | 13.3 °C | 78.74 mm |
| December | -0.8 °C | 7.9 °C | 107.19 mm |
| Annual | 7.9 °C | 18.3 °C | 1200.66 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 | Cfa - Humid Subtropical Climate |