Mount Royal, New Jersey has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 47.5 °F (low) to 64.7 °F (high). Annual precipitation averages 46.8 Inches. Mount Royal is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 26.5 °F | 41.4 °F | 3.62 in. |
| February | 27.8 °F | 43.8 °F | 2.84 in. |
| March | 34.4 °F | 51.6 °F | 4.42 in. |
| April | 44.8 °F | 63.8 °F | 3.54 in. |
| May | 54.4 °F | 73.4 °F | 3.7 in. |
| June | 64.0 °F | 82.8 °F | 4.25 in. |
| July | 69.5 °F | 87.0 °F | 4.6 in. |
| August | 68.0 °F | 85.1 °F | 4.62 in. |
| September | 61.1 °F | 78.5 °F | 4.14 in. |
| October | 49.1 °F | 66.7 °F | 3.87 in. |
| November | 38.9 °F | 55.8 °F | 3.05 in. |
| December | 31.9 °F | 46.3 °F | 4.19 in. |
| Annual | 47.5 °F | 64.7 °F | 46.84 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |