Arco, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.2 °C (low) to 12 °C (high). Annual precipitation averages 694.4 Millimeters. Arco is located in USDA Plant Hardiness Zone 5a. 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 | -14.8 °C | -5.3 °C | 17.78 mm |
| February | -12.7 °C | -2.8 °C | 21.84 mm |
| March | -6.2 °C | 3.7 °C | 35.81 mm |
| April | 0.4 °C | 11.9 °C | 70.87 mm |
| May | 7.7 °C | 19.3 °C | 87.12 mm |
| June | 13.8 °C | 24.9 °C | 101.6 mm |
| July | 16.1 °C | 27.3 °C | 91.44 mm |
| August | 14.6 °C | 26 °C | 82.55 mm |
| September | 9.8 °C | 22.3 °C | 79.25 mm |
| October | 2.3 °C | 14.2 °C | 51.82 mm |
| November | -4.9 °C | 5.1 °C | 28.45 mm |
| December | -11.4 °C | -2.6 °C | 25.91 mm |
| Annual | 1.2 °C | 12 °C | 694.44 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |