South Yarmouth, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 44.3 °F (low) to 57.6 °F (high). Annual precipitation averages 48.7 Inches. South Yarmouth is located in USDA Plant Hardiness Zone 7b. 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 | 25.0 °F | 38.2 °F | 4.47 in. |
| February | 25.6 °F | 39.0 °F | 3.7 in. |
| March | 30.8 °F | 43.8 °F | 4.65 in. |
| April | 39.2 °F | 52.6 °F | 4.48 in. |
| May | 48.4 °F | 62.1 °F | 3.43 in. |
| June | 57.6 °F | 71.1 °F | 3.43 in. |
| July | 64.8 °F | 78.1 °F | 2.84 in. |
| August | 64.1 °F | 77.3 °F | 3.29 in. |
| September | 58.2 °F | 71.5 °F | 4.36 in. |
| October | 48.2 °F | 61.4 °F | 4.66 in. |
| November | 39.1 °F | 52.2 °F | 4.02 in. |
| December | 31.0 °F | 44.0 °F | 5.38 in. |
| Annual | 44.3 °F | 57.6 °F | 48.71 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Dfb - Humid Continental Mild Summer, Wet All Year |