South Duxbury, Massachusetts has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.9 °F (low) to 59.9 °F (high). Annual precipitation averages 52.4 Inches. South Duxbury is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.8 °F | 38.7 °F | 4.46 in. |
| February | 23.8 °F | 40.2 °F | 4.05 in. |
| March | 29.4 °F | 46.1 °F | 5.66 in. |
| April | 38.3 °F | 56.4 °F | 4.6 in. |
| May | 48.2 °F | 66.5 °F | 3.74 in. |
| June | 57.4 °F | 75.7 °F | 3.9 in. |
| July | 63.9 °F | 81.6 °F | 3.5 in. |
| August | 62.7 °F | 79.8 °F | 3.69 in. |
| September | 56.2 °F | 73.5 °F | 4.22 in. |
| October | 46.1 °F | 63.0 °F | 4.89 in. |
| November | 36.7 °F | 53.1 °F | 4.64 in. |
| December | 28.9 °F | 44.3 °F | 5.06 in. |
| Annual | 42.9 °F | 59.9 °F | 52.41 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |