Sister Bay, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37 °F (low) to 52.4 °F (high). Annual precipitation averages 30.9 Inches. Sister Bay 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.8 °F | 26.1 °F | 1.76 in. |
| February | 13.1 °F | 28.4 °F | 1.0 in. |
| March | 21.9 °F | 38.0 °F | 1.67 in. |
| April | 32.6 °F | 49.3 °F | 2.8 in. |
| May | 43.6 °F | 62.1 °F | 3.44 in. |
| June | 53.9 °F | 72.2 °F | 3.32 in. |
| July | 59.5 °F | 77.3 °F | 2.94 in. |
| August | 59.8 °F | 76.2 °F | 3.18 in. |
| September | 52.4 °F | 68.6 °F | 3.36 in. |
| October | 42.1 °F | 56.0 °F | 3.41 in. |
| November | 31.4 °F | 43.0 °F | 2.29 in. |
| December | 21.1 °F | 32.1 °F | 1.68 in. |
| Annual | 37 °F | 52.4 °F | 30.85 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |