Blair, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.1 °C (low) to 13.2 °C (high). Annual precipitation averages 894.8 Millimeters. Blair 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.9 °C | -3.9 °C | 25.91 mm |
| February | -12.9 °C | -1.2 °C | 26.16 mm |
| March | -6.2 °C | 5.8 °C | 46.99 mm |
| April | 0.6 °C | 13.6 °C | 87.12 mm |
| May | 7.3 °C | 20.7 °C | 115.06 mm |
| June | 13.1 °C | 25.7 °C | 136.4 mm |
| July | 15.2 °C | 27.9 °C | 102.11 mm |
| August | 13.9 °C | 26.8 °C | 104.39 mm |
| September | 9.3 °C | 22.7 °C | 106.43 mm |
| October | 2.5 °C | 15.1 °C | 67.56 mm |
| November | -3.8 °C | 6.3 °C | 44.7 mm |
| December | -10.7 °C | -0.9 °C | 32 mm |
| Annual | 1.1 °C | 13.2 °C | 894.83 mm |
| 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 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |