Finlayson, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30.5 °F (low) to 52.1 °F (high). Annual precipitation averages 31.9 Inches. Finlayson is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.2 °F | 20.3 °F | 0.79 in. |
| February | 4.0 °F | 25.9 °F | 0.85 in. |
| March | 16.6 °F | 38.1 °F | 1.53 in. |
| April | 29.6 °F | 52.4 °F | 2.67 in. |
| May | 41.5 °F | 66.1 °F | 3.65 in. |
| June | 51.4 °F | 75.1 °F | 4.48 in. |
| July | 56.7 °F | 79.7 °F | 4.62 in. |
| August | 54.4 °F | 77.7 °F | 4.05 in. |
| September | 46.1 °F | 69.7 °F | 3.39 in. |
| October | 34.5 °F | 55.2 °F | 3.04 in. |
| November | 22.2 °F | 38.8 °F | 1.62 in. |
| December | 9.0 °F | 25.6 °F | 1.18 in. |
| Annual | 30.5 °F | 52.1 °F | 31.87 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |