Marathon, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.9 °F (low) to 56.8 °F (high). Annual precipitation averages 44.9 Inches. Marathon 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 | 14.7 °F | 31.6 °F | 3.0 in. |
| February | 15.5 °F | 33.7 °F | 2.81 in. |
| March | 22.4 °F | 41.5 °F | 3.29 in. |
| April | 34.0 °F | 55.4 °F | 3.9 in. |
| May | 45.0 °F | 67.9 °F | 3.93 in. |
| June | 54.0 °F | 76.2 °F | 5.0 in. |
| July | 58.7 °F | 80.3 °F | 4.09 in. |
| August | 57.0 °F | 79.2 °F | 4.41 in. |
| September | 49.9 °F | 72.4 °F | 3.9 in. |
| October | 39.5 °F | 59.9 °F | 3.8 in. |
| November | 30.5 °F | 47.2 °F | 3.56 in. |
| December | 22.0 °F | 36.5 °F | 3.24 in. |
| Annual | 36.9 °F | 56.8 °F | 44.93 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 5b : -15°F to -10°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 |