Sayner, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.2 °C (low) to 10.4 °C (high). Annual precipitation averages 843 Millimeters. Sayner is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.2 °C | -5.9 °C | 32.26 mm |
| February | -15.7 °C | -3.3 °C | 28.19 mm |
| March | -10.3 °C | 3.1 °C | 41.15 mm |
| April | -2.9 °C | 9.9 °C | 72.14 mm |
| May | 4.7 °C | 17.9 °C | 91.44 mm |
| June | 10.4 °C | 22.9 °C | 111.51 mm |
| July | 12.8 °C | 24.9 °C | 104.9 mm |
| August | 11.7 °C | 23.8 °C | 88.14 mm |
| September | 7.4 °C | 19.5 °C | 93.47 mm |
| October | 0.9 °C | 11.6 °C | 88.65 mm |
| November | -5.3 °C | 3.3 °C | 51.31 mm |
| December | -12.1 °C | -3.3 °C | 39.88 mm |
| Annual | -1.2 °C | 10.4 °C | 843.04 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |