Myrtle, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.3 °F (low) to 54.3 °F (high). Annual precipitation averages 35.5 Inches. Myrtle is located in USDA Plant Hardiness Zone 5a. 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 | 6.1 °F | 22.7 °F | 0.98 in. |
| February | 10.0 °F | 27.2 °F | 1.0 in. |
| March | 22.4 °F | 39.6 °F | 1.94 in. |
| April | 34.6 °F | 55.1 °F | 3.59 in. |
| May | 47.1 °F | 67.7 °F | 4.75 in. |
| June | 58.0 °F | 77.7 °F | 5.19 in. |
| July | 61.3 °F | 81.0 °F | 4.83 in. |
| August | 58.6 °F | 78.7 °F | 4.18 in. |
| September | 50.0 °F | 72.5 °F | 3.55 in. |
| October | 37.3 °F | 58.7 °F | 2.56 in. |
| November | 25.2 °F | 42.4 °F | 1.59 in. |
| December | 13.2 °F | 28.5 °F | 1.29 in. |
| Annual | 35.3 °F | 54.3 °F | 35.45 in. |
| 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 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |