Junction City, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.1 °C (low) to 12 °C (high). Annual precipitation averages 850.1 Millimeters. Junction City is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.2 °C | -4.7 °C | 29.21 mm |
| February | -12.9 °C | -2.2 °C | 26.67 mm |
| March | -6.7 °C | 4.4 °C | 43.18 mm |
| April | 0.4 °C | 12.2 °C | 81.28 mm |
| May | 7.2 °C | 19.2 °C | 99.82 mm |
| June | 12.8 °C | 24.3 °C | 119.89 mm |
| July | 14.9 °C | 26.8 °C | 96.52 mm |
| August | 13.8 °C | 25.6 °C | 102.62 mm |
| September | 9.3 °C | 21.4 °C | 93.22 mm |
| October | 2.7 °C | 13.7 °C | 72.64 mm |
| November | -3.7 °C | 5.4 °C | 47.24 mm |
| December | -10.3 °C | -1.8 °C | 37.85 mm |
| Annual | 1.1 °C | 12 °C | 850.14 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |