Millstone, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.1 °F (low) to 63.6 °F (high). Annual precipitation averages 48.6 Inches. Millstone 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 | 22.2 °F | 39.6 °F | 3.62 in. |
| February | 23.5 °F | 42.3 °F | 2.79 in. |
| March | 30.6 °F | 50.4 °F | 4.22 in. |
| April | 40.7 °F | 62.7 °F | 3.86 in. |
| May | 50.5 °F | 72.6 °F | 4.03 in. |
| June | 59.4 °F | 81.4 °F | 4.53 in. |
| July | 64.8 °F | 86.3 °F | 4.93 in. |
| August | 63.3 °F | 84.3 °F | 4.58 in. |
| September | 55.9 °F | 77.8 °F | 4.17 in. |
| October | 44.5 °F | 65.7 °F | 4.24 in. |
| November | 34.3 °F | 55.1 °F | 3.35 in. |
| December | 27.3 °F | 44.7 °F | 4.26 in. |
| Annual | 43.1 °F | 63.6 °F | 48.58 in. |
| 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 : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |