Roseau, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.6 °F (low) to 48.2 °F (high). Annual precipitation averages 24.4 Inches. Roseau is located in USDA Plant Hardiness Zone 3b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.2 °F | 13.4 °F | 0.72 in. |
| February | -2.7 °F | 18.5 °F | 0.55 in. |
| March | 11.7 °F | 32.2 °F | 0.72 in. |
| April | 27.9 °F | 49.1 °F | 1.27 in. |
| May | 40.6 °F | 63.5 °F | 3.19 in. |
| June | 51.8 °F | 73.0 °F | 4.42 in. |
| July | 55.5 °F | 78.1 °F | 3.62 in. |
| August | 52.7 °F | 76.9 °F | 2.96 in. |
| September | 44.4 °F | 68.2 °F | 2.91 in. |
| October | 32.4 °F | 51.7 °F | 2.08 in. |
| November | 18.4 °F | 34.2 °F | 0.97 in. |
| December | 3.5 °F | 19.9 °F | 0.97 in. |
| Annual | 27.6 °F | 48.2 °F | 24.38 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 3b : -35°F to -30°F |
| Plant Hardiness Zone - 2012 | Zone 3a : -40°F to -35°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |