Marlboro, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40.6 °F (low) to 59.4 °F (high). Annual precipitation averages 40.9 Inches. Marlboro 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 | 18.9 °F | 33.7 °F | 2.95 in. |
| February | 19.8 °F | 36.5 °F | 2.27 in. |
| March | 27.9 °F | 46.1 °F | 3.18 in. |
| April | 38.6 °F | 59.5 °F | 3.69 in. |
| May | 48.7 °F | 69.8 °F | 4.03 in. |
| June | 58.2 °F | 78.7 °F | 4.4 in. |
| July | 61.9 °F | 82.5 °F | 4.24 in. |
| August | 60.0 °F | 80.5 °F | 3.57 in. |
| September | 53.2 °F | 74.4 °F | 3.51 in. |
| October | 42.2 °F | 62.7 °F | 3.21 in. |
| November | 32.8 °F | 49.5 °F | 2.93 in. |
| December | 24.6 °F | 38.6 °F | 2.88 in. |
| Annual | 40.6 °F | 59.4 °F | 40.86 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 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |