Isanti, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.7 °C (low) to 12.1 °C (high). Annual precipitation averages 811.8 Millimeters. Isanti is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.9 °C | -5.6 °C | 20.32 mm |
| February | -14 °C | -2.7 °C | 20.57 mm |
| March | -7.1 °C | 4.3 °C | 38.35 mm |
| April | 0.2 °C | 12.4 °C | 73.66 mm |
| May | 7.2 °C | 19.9 °C | 104.65 mm |
| June | 12.8 °C | 24.9 °C | 115.32 mm |
| July | 15.4 °C | 27.4 °C | 111 mm |
| August | 14 °C | 26.2 °C | 104.39 mm |
| September | 9.3 °C | 21.8 °C | 82.3 mm |
| October | 2.5 °C | 13.9 °C | 71.37 mm |
| November | -4.4 °C | 4.9 °C | 41.91 mm |
| December | -11.7 °C | -2.7 °C | 27.94 mm |
| Annual | 0.7 °C | 12.1 °C | 811.78 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |