Rothsay, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.5 °F (low) to 51.6 °F (high). Annual precipitation averages 25.3 Inches. Rothsay is located in USDA Plant Hardiness Zone 4a. 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 | 0.4 °F | 18.0 °F | 0.72 in. |
| February | 3.9 °F | 22.5 °F | 0.65 in. |
| March | 18.1 °F | 35.8 °F | 1.08 in. |
| April | 32.3 °F | 52.5 °F | 1.81 in. |
| May | 45.4 °F | 66.6 °F | 3.33 in. |
| June | 56.6 °F | 76.0 °F | 4.22 in. |
| July | 60.6 °F | 80.0 °F | 3.62 in. |
| August | 58.2 °F | 78.9 °F | 2.83 in. |
| September | 49.3 °F | 70.8 °F | 2.85 in. |
| October | 35.8 °F | 55.3 °F | 2.51 in. |
| November | 21.8 °F | 38.2 °F | 0.87 in. |
| December | 8.1 °F | 24.2 °F | 0.83 in. |
| Annual | 32.5 °F | 51.6 °F | 25.32 in. |
| 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 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |