Rockland, Massachusetts has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5 °C (low) to 15.8 °C (high). Annual precipitation averages 1290.3 Millimeters. Rockland is located in USDA Plant Hardiness Zone 6b. 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 | -6.9 °C | 2.9 °C | 108.71 mm |
| February | -6.2 °C | 4.2 °C | 96.27 mm |
| March | -2.2 °C | 8.1 °C | 135.89 mm |
| April | 3.2 °C | 14.4 °C | 117.6 mm |
| May | 8.6 °C | 20.2 °C | 90.68 mm |
| June | 13.8 °C | 25.2 °C | 96.01 mm |
| July | 17.3 °C | 28.4 °C | 86.11 mm |
| August | 16.4 °C | 27.7 °C | 91.95 mm |
| September | 12.4 °C | 23.7 °C | 95.5 mm |
| October | 6.2 °C | 17.3 °C | 129.03 mm |
| November | 1 °C | 11.4 °C | 113.28 mm |
| December | -3.6 °C | 6 °C | 129.29 mm |
| Annual | 5 °C | 15.8 °C | 1290.32 mm |
| 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |