Helmetta, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.8 °C (low) to 17.8 °C (high). Annual precipitation averages 1234.5 Millimeters. Helmetta is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.7 °C | 4.5 °C | 91.95 mm |
| February | -3.9 °C | 6 °C | 70.87 mm |
| March | -0.1 °C | 10.4 °C | 109.22 mm |
| April | 5.4 °C | 17.2 °C | 97.54 mm |
| May | 10.8 °C | 22.7 °C | 101.35 mm |
| June | 15.7 °C | 27.7 °C | 115.82 mm |
| July | 18.8 °C | 30.4 °C | 123.95 mm |
| August | 17.9 °C | 29.2 °C | 115.57 mm |
| September | 13.9 °C | 25.7 °C | 106.68 mm |
| October | 7.6 °C | 18.9 °C | 104.14 mm |
| November | 1.9 °C | 13.1 °C | 86.36 mm |
| December | -2 °C | 7.4 °C | 111 mm |
| Annual | 6.8 °C | 17.8 °C | 1234.45 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°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 |