Hamilton Square, New Jersey has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.1 °C (low) to 17.7 °C (high). Annual precipitation averages 1212.1 Millimeters. Hamilton Square 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 | -4.4 °C | 4.7 °C | 89.41 mm |
| February | -3.6 °C | 6.1 °C | 66.8 mm |
| March | 0.2 °C | 10.4 °C | 109.98 mm |
| April | 5.8 °C | 17.2 °C | 90.42 mm |
| May | 11.1 °C | 22.4 °C | 102.62 mm |
| June | 16.2 °C | 27.6 °C | 114.55 mm |
| July | 19.2 °C | 30.1 °C | 127.25 mm |
| August | 18.3 °C | 29.1 °C | 115.82 mm |
| September | 14.2 °C | 25.6 °C | 104.39 mm |
| October | 7.8 °C | 18.9 °C | 98.04 mm |
| November | 2.3 °C | 13.1 °C | 84.07 mm |
| December | -1.8 °C | 7.4 °C | 108.71 mm |
| Annual | 7.1 °C | 17.7 °C | 1212.06 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 | Cfa - Humid Subtropical Climate |