Barrett, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.3 °C (low) to 11.3 °C (high). Annual precipitation averages 668.3 Millimeters. Barrett 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17.1 °C | -7.2 °C | 18.29 mm |
| February | -15.2 °C | -4.7 °C | 18.29 mm |
| March | -7.6 °C | 2.6 °C | 30.48 mm |
| April | 0.1 °C | 11.7 °C | 54.61 mm |
| May | 7.4 °C | 19.6 °C | 80.26 mm |
| June | 13.4 °C | 24.7 °C | 112.01 mm |
| July | 15.8 °C | 26.9 °C | 94.49 mm |
| August | 14.2 °C | 26.1 °C | 80.52 mm |
| September | 9.3 °C | 21.9 °C | 68.83 mm |
| October | 2.1 °C | 13.3 °C | 63.5 mm |
| November | -5.6 °C | 3.9 °C | 24.64 mm |
| December | -12.9 °C | -3.8 °C | 22.35 mm |
| Annual | 0.3 °C | 11.3 °C | 668.27 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 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 |