Mason, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.9 °F (low) to 57.4 °F (high). Annual precipitation averages 49.9 Inches. Mason 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 | 14.0 °F | 32.2 °F | 3.61 in. |
| February | 15.5 °F | 35.2 °F | 3.35 in. |
| March | 23.2 °F | 43.0 °F | 4.3 in. |
| April | 34.0 °F | 56.0 °F | 4.19 in. |
| May | 44.9 °F | 67.3 °F | 3.95 in. |
| June | 54.2 °F | 76.1 °F | 4.41 in. |
| July | 59.7 °F | 81.3 °F | 4.12 in. |
| August | 57.8 °F | 79.6 °F | 3.97 in. |
| September | 50.4 °F | 72.5 °F | 4.17 in. |
| October | 38.8 °F | 59.6 °F | 5.19 in. |
| November | 29.5 °F | 48.3 °F | 4.04 in. |
| December | 20.5 °F | 37.6 °F | 4.55 in. |
| Annual | 36.9 °F | 57.4 °F | 49.85 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 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |