Raritan, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6 °C (low) to 17.4 °C (high). Annual precipitation averages 1225.8 Millimeters. Raritan 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 | -5.7 °C | 4.1 °C | 90.68 mm |
| February | -4.9 °C | 5.6 °C | 69.85 mm |
| March | -1 °C | 10.1 °C | 105.41 mm |
| April | 4.7 °C | 16.9 °C | 97.54 mm |
| May | 10.1 °C | 22.4 °C | 103.38 mm |
| June | 15.1 °C | 27.3 °C | 114.81 mm |
| July | 18.1 °C | 30.1 °C | 123.7 mm |
| August | 17.2 °C | 28.9 °C | 116.84 mm |
| September | 13.2 °C | 25.3 °C | 105.66 mm |
| October | 6.8 °C | 18.6 °C | 108.2 mm |
| November | 1.1 °C | 12.6 °C | 83.82 mm |
| December | -2.7 °C | 6.9 °C | 105.92 mm |
| Annual | 6 °C | 17.4 °C | 1225.81 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |