Cosmos, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.2 °C (low) to 12.1 °C (high). Annual precipitation averages 763.8 Millimeters. Cosmos 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 | -15.6 °C | -5.9 °C | 18.8 mm |
| February | -13.8 °C | -3.4 °C | 21.34 mm |
| March | -6.6 °C | 3.5 °C | 38.61 mm |
| April | 0.9 °C | 12.6 °C | 68.07 mm |
| May | 8.1 °C | 20 °C | 95.76 mm |
| June | 14.2 °C | 25.4 °C | 125.73 mm |
| July | 16.3 °C | 27.6 °C | 94.49 mm |
| August | 14.8 °C | 26.3 °C | 101.35 mm |
| September | 10 °C | 22.5 °C | 80.52 mm |
| October | 2.7 °C | 14.3 °C | 59.69 mm |
| November | -4.6 °C | 4.9 °C | 34.04 mm |
| December | -11.6 °C | -2.9 °C | 25.4 mm |
| Annual | 1.2 °C | 12.1 °C | 763.8 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 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |