Isle, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.7 °C (low) to 10.6 °C (high). Annual precipitation averages 781.8 Millimeters. Isle is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -18 °C | -7 °C | 16.26 mm |
| February | -16.1 °C | -3.8 °C | 19.81 mm |
| March | -8.9 °C | 3 °C | 37.85 mm |
| April | -1.1 °C | 10.8 °C | 66.55 mm |
| May | 5.8 °C | 18.2 °C | 92.2 mm |
| June | 11.5 °C | 23.4 °C | 116.08 mm |
| July | 13.9 °C | 25.9 °C | 113.28 mm |
| August | 12.6 °C | 24.8 °C | 100.33 mm |
| September | 8.2 °C | 20.3 °C | 76.96 mm |
| October | 1.7 °C | 12.3 °C | 77.72 mm |
| November | -5.3 °C | 3.4 °C | 38.35 mm |
| December | -12.8 °C | -3.9 °C | 26.42 mm |
| Annual | -0.7 °C | 10.6 °C | 781.81 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |