Round Lake, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.5 °F (low) to 58.9 °F (high). Annual precipitation averages 43.9 Inches. Round Lake is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.8 °F | 32.3 °F | 3.08 in. |
| February | 17.1 °F | 35.3 °F | 2.49 in. |
| March | 25.5 °F | 44.2 °F | 3.21 in. |
| April | 36.9 °F | 58.7 °F | 3.58 in. |
| May | 48.5 °F | 70.6 °F | 3.6 in. |
| June | 57.6 °F | 78.8 °F | 4.65 in. |
| July | 62.2 °F | 83.6 °F | 4.63 in. |
| August | 60.9 °F | 81.3 °F | 4.14 in. |
| September | 53.2 °F | 74.2 °F | 3.78 in. |
| October | 41.9 °F | 61.3 °F | 4.16 in. |
| November | 31.9 °F | 48.7 °F | 3.14 in. |
| December | 23.0 °F | 37.5 °F | 3.48 in. |
| Annual | 39.5 °F | 58.9 °F | 43.94 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |