Royalton, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.9 °F (low) to 55.8 °F (high). Annual precipitation averages 43 Inches. Royalton is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.5 °F | 28.5 °F | 2.98 in. |
| February | 8.5 °F | 31.8 °F | 2.59 in. |
| March | 17.9 °F | 40.4 °F | 3.22 in. |
| April | 30.2 °F | 54.5 °F | 3.38 in. |
| May | 42.0 °F | 68.1 °F | 3.4 in. |
| June | 51.0 °F | 76.4 °F | 4.44 in. |
| July | 56.4 °F | 81.3 °F | 4.49 in. |
| August | 54.6 °F | 78.9 °F | 3.93 in. |
| September | 47.4 °F | 72.2 °F | 3.48 in. |
| October | 36.1 °F | 58.4 °F | 4.13 in. |
| November | 26.5 °F | 45.5 °F | 3.18 in. |
| December | 16.1 °F | 33.7 °F | 3.76 in. |
| Annual | 32.9 °F | 55.8 °F | 42.98 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |