Altamont, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.4 °C (low) to 14.4 °C (high). Annual precipitation averages 1050.5 Millimeters. Altamont is located in USDA Plant Hardiness Zone 5b. 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 | -9.7 °C | -0.3 °C | 62.23 mm |
| February | -9 °C | 1.3 °C | 61.72 mm |
| March | -4.4 °C | 6.2 °C | 84.33 mm |
| April | 2 °C | 14 °C | 87.12 mm |
| May | 8.4 °C | 20.7 °C | 90.17 mm |
| June | 13.4 °C | 25.3 °C | 109.98 mm |
| July | 16.1 °C | 27.9 °C | 113.28 mm |
| August | 15.2 °C | 27 °C | 91.44 mm |
| September | 10.8 °C | 23 °C | 84.07 mm |
| October | 4.7 °C | 15.7 °C | 112.78 mm |
| November | -0.9 °C | 8.9 °C | 67.31 mm |
| December | -5.7 °C | 2.7 °C | 86.11 mm |
| Annual | 3.4 °C | 14.4 °C | 1050.54 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |