Onekama, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.7 °F (low) to 54.4 °F (high). Annual precipitation averages 35.4 Inches. Onekama is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.8 °F | 29.0 °F | 2.21 in. |
| February | 17.8 °F | 31.3 °F | 1.61 in. |
| March | 23.5 °F | 39.9 °F | 2.02 in. |
| April | 33.7 °F | 52.2 °F | 3.36 in. |
| May | 44.1 °F | 64.7 °F | 3.4 in. |
| June | 53.3 °F | 74.3 °F | 3.41 in. |
| July | 58.4 °F | 78.1 °F | 3.15 in. |
| August | 57.5 °F | 76.9 °F | 3.24 in. |
| September | 50.4 °F | 70.5 °F | 3.5 in. |
| October | 40.4 °F | 57.4 °F | 4.07 in. |
| November | 31.7 °F | 44.7 °F | 3.01 in. |
| December | 23.3 °F | 34.0 °F | 2.44 in. |
| Annual | 37.7 °F | 54.4 °F | 35.42 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°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 |