Erma, New Jersey has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 48.9 °F (low) to 63.1 °F (high). Annual precipitation averages 44.7 Inches. Erma is located in USDA Plant Hardiness Zone 8a. 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 | 28.7 °F | 42.9 °F | 3.25 in. |
| February | 29.5 °F | 44.1 °F | 2.86 in. |
| March | 36.1 °F | 50.3 °F | 4.34 in. |
| April | 45.7 °F | 59.6 °F | 3.48 in. |
| May | 54.6 °F | 68.9 °F | 3.59 in. |
| June | 64.4 °F | 78.0 °F | 3.51 in. |
| July | 69.7 °F | 83.5 °F | 4.19 in. |
| August | 68.6 °F | 82.2 °F | 4.09 in. |
| September | 62.9 °F | 77.0 °F | 3.59 in. |
| October | 51.9 °F | 66.5 °F | 4.32 in. |
| November | 41.2 °F | 56.2 °F | 3.3 in. |
| December | 33.7 °F | 47.7 °F | 4.15 in. |
| Annual | 48.9 °F | 63.1 °F | 44.67 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |