Holyoke, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.1 °C (low) to 15.5 °C (high). Annual precipitation averages 1180.6 Millimeters. Holyoke 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 | -8.7 °C | 1.3 °C | 83.57 mm |
| February | -8 °C | 2.9 °C | 72.64 mm |
| March | -3.2 °C | 7.6 °C | 91.69 mm |
| April | 2.8 °C | 15.1 °C | 95 mm |
| May | 8.6 °C | 21.3 °C | 93.73 mm |
| June | 13.7 °C | 25.9 °C | 112.52 mm |
| July | 16.8 °C | 28.8 °C | 100.58 mm |
| August | 15.8 °C | 27.9 °C | 108.97 mm |
| September | 11.5 °C | 23.9 °C | 115.32 mm |
| October | 5.1 °C | 16.9 °C | 120.65 mm |
| November | -0.2 °C | 10.3 °C | 84.58 mm |
| December | -5.1 °C | 4.3 °C | 101.35 mm |
| Annual | 4.1 °C | 15.5 °C | 1180.6 mm |
| 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 : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |