Grand River, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 43.2 °F (low) to 58 °F (high). Annual precipitation averages 41.5 Inches. Grand River is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.4 °F | 34.5 °F | 3.13 in. |
| February | 21.7 °F | 35.9 °F | 2.19 in. |
| March | 28.4 °F | 43.1 °F | 2.89 in. |
| April | 39.4 °F | 56.2 °F | 3.63 in. |
| May | 50.6 °F | 67.0 °F | 3.51 in. |
| June | 60.2 °F | 76.0 °F | 3.61 in. |
| July | 64.8 °F | 79.8 °F | 4.25 in. |
| August | 63.6 °F | 78.9 °F | 3.65 in. |
| September | 56.9 °F | 73.3 °F | 4.02 in. |
| October | 46.4 °F | 61.8 °F | 4.08 in. |
| November | 36.7 °F | 50.1 °F | 3.41 in. |
| December | 28.0 °F | 39.5 °F | 3.14 in. |
| Annual | 43.2 °F | 58 °F | 41.51 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |