Norwell, Massachusetts has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.4 °F (low) to 60 °F (high). Annual precipitation averages 51.8 Inches. Norwell 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.1 °F | 37.4 °F | 4.34 in. |
| February | 22.3 °F | 39.5 °F | 3.97 in. |
| March | 29.1 °F | 46.0 °F | 5.48 in. |
| April | 38.9 °F | 57.4 °F | 4.65 in. |
| May | 48.6 °F | 67.5 °F | 3.64 in. |
| June | 58.1 °F | 76.8 °F | 3.82 in. |
| July | 64.3 °F | 82.6 °F | 3.47 in. |
| August | 63.0 °F | 81.2 °F | 3.69 in. |
| September | 56.1 °F | 74.1 °F | 3.87 in. |
| October | 45.1 °F | 62.8 °F | 5.2 in. |
| November | 35.5 °F | 52.3 °F | 4.56 in. |
| December | 27.2 °F | 42.9 °F | 5.12 in. |
| Annual | 42.4 °F | 60 °F | 51.81 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 |