Port Republic, New Jersey has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.5 °C (low) to 17.6 °C (high). Annual precipitation averages 1210.3 Millimeters. Port Republic is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.1 °C | 5.7 °C | 93.73 mm |
| February | -3.5 °C | 6.7 °C | 76.71 mm |
| March | 0.3 °C | 10.3 °C | 119.63 mm |
| April | 5.8 °C | 16.4 °C | 90.17 mm |
| May | 11.2 °C | 21.6 °C | 89.15 mm |
| June | 16.5 °C | 26.7 °C | 97.54 mm |
| July | 19.6 °C | 29.3 °C | 119.63 mm |
| August | 18.7 °C | 28.5 °C | 120.9 mm |
| September | 15.1 °C | 25.3 °C | 93.22 mm |
| October | 8.4 °C | 19.3 °C | 107.44 mm |
| November | 2.7 °C | 13.5 °C | 87.38 mm |
| December | -1.2 °C | 8.3 °C | 114.81 mm |
| Annual | 7.5 °C | 17.6 °C | 1210.31 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |