Lena, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1 °C (low) to 12.3 °C (high). Annual precipitation averages 839 Millimeters. Lena is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.4 °C | -3.8 °C | 39.88 mm |
| February | -12.7 °C | -1.8 °C | 29.46 mm |
| March | -7 °C | 4.4 °C | 47.24 mm |
| April | -0.2 °C | 11.8 °C | 80.26 mm |
| May | 6.4 °C | 19.2 °C | 89.66 mm |
| June | 12.1 °C | 24.3 °C | 105.92 mm |
| July | 14.4 °C | 26.9 °C | 96.27 mm |
| August | 13.4 °C | 25.8 °C | 86.11 mm |
| September | 8.9 °C | 21.7 °C | 88.14 mm |
| October | 2.6 °C | 14.1 °C | 78.23 mm |
| November | -3.3 °C | 6.2 °C | 51.82 mm |
| December | -9.6 °C | -0.9 °C | 45.97 mm |
| Annual | 1 °C | 12.3 °C | 838.96 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |