South Hadley, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.8 °F (low) to 59.8 °F (high). Annual precipitation averages 46.6 Inches. South Hadley is located in USDA Plant Hardiness Zone 6a. 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 | 15.8 °F | 34.1 °F | 3.3 in. |
| February | 17.0 °F | 37.1 °F | 2.89 in. |
| March | 25.8 °F | 45.4 °F | 3.64 in. |
| April | 36.5 °F | 58.9 °F | 3.77 in. |
| May | 47.0 °F | 70.2 °F | 3.65 in. |
| June | 56.2 °F | 78.5 °F | 4.39 in. |
| July | 61.6 °F | 83.8 °F | 3.97 in. |
| August | 59.9 °F | 82.1 °F | 4.24 in. |
| September | 52.1 °F | 74.9 °F | 4.52 in. |
| October | 40.7 °F | 62.3 °F | 4.79 in. |
| November | 31.0 °F | 50.2 °F | 3.37 in. |
| December | 22.5 °F | 39.5 °F | 4.03 in. |
| Annual | 38.8 °F | 59.8 °F | 46.56 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |