Portlandville, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.3 °F (low) to 56.8 °F (high). Annual precipitation averages 44.5 Inches. Portlandville is located in USDA Plant Hardiness Zone 5b. 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 | 13.3 °F | 31.5 °F | 3.27 in. |
| February | 14.2 °F | 34.2 °F | 2.69 in. |
| March | 21.2 °F | 42.3 °F | 3.46 in. |
| April | 32.1 °F | 56.0 °F | 3.86 in. |
| May | 42.7 °F | 68.2 °F | 3.64 in. |
| June | 52.2 °F | 75.9 °F | 4.44 in. |
| July | 56.7 °F | 80.0 °F | 4.51 in. |
| August | 55.3 °F | 78.5 °F | 4.01 in. |
| September | 48.5 °F | 71.8 °F | 3.87 in. |
| October | 38.0 °F | 59.4 °F | 3.89 in. |
| November | 28.7 °F | 46.9 °F | 3.29 in. |
| December | 20.9 °F | 36.4 °F | 3.54 in. |
| Annual | 35.3 °F | 56.8 °F | 44.47 in. |
| 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |