Hollis, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.9 °C (low) to 14.7 °C (high). Annual precipitation averages 1213.6 Millimeters. Hollis 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 | -9.8 °C | 0.7 °C | 88.14 mm |
| February | -8.9 °C | 2.3 °C | 82.8 mm |
| March | -4.5 °C | 6.7 °C | 105.16 mm |
| April | 1.3 °C | 13.9 °C | 102.62 mm |
| May | 7.3 °C | 20.1 °C | 96.27 mm |
| June | 12.5 °C | 25.1 °C | 111.25 mm |
| July | 15.6 °C | 28.1 °C | 95.25 mm |
| August | 14.5 °C | 27.1 °C | 97.54 mm |
| September | 10.2 °C | 23.1 °C | 101.85 mm |
| October | 3.7 °C | 15.9 °C | 122.94 mm |
| November | -1.4 °C | 9.7 °C | 97.79 mm |
| December | -6.2 °C | 3.7 °C | 112.01 mm |
| Annual | 2.9 °C | 14.7 °C | 1213.62 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |