Mountain Lakes, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.2 °C (low) to 13 °C (high). Annual precipitation averages 1012.5 Millimeters. Mountain Lakes is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.7 °C | -2.1 °C | 61.47 mm |
| February | -13.5 °C | -0.3 °C | 53.09 mm |
| March | -8 °C | 4.7 °C | 62.74 mm |
| April | -1.2 °C | 12.3 °C | 80.01 mm |
| May | 5.4 °C | 19.6 °C | 88.39 mm |
| June | 10.5 °C | 24.2 °C | 100.58 mm |
| July | 13.4 °C | 26.9 °C | 108.71 mm |
| August | 12.3 °C | 26.2 °C | 96.01 mm |
| September | 8.3 °C | 22.1 °C | 93.73 mm |
| October | 1.9 °C | 14.4 °C | 111.76 mm |
| November | -3.3 °C | 7.3 °C | 72.39 mm |
| December | -9.2 °C | 0.8 °C | 83.57 mm |
| Annual | 0.2 °C | 13 °C | 1012.45 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |