Ostrander, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.8 °F (low) to 53.4 °F (high). Annual precipitation averages 35.1 Inches. Ostrander 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 | 6.1 °F | 22.0 °F | 0.89 in. |
| February | 10.0 °F | 26.5 °F | 0.96 in. |
| March | 21.7 °F | 38.9 °F | 1.74 in. |
| April | 34.0 °F | 54.1 °F | 3.71 in. |
| May | 46.4 °F | 66.7 °F | 4.6 in. |
| June | 57.0 °F | 76.5 °F | 5.73 in. |
| July | 60.2 °F | 79.8 °F | 4.26 in. |
| August | 57.6 °F | 77.7 °F | 4.15 in. |
| September | 49.4 °F | 71.4 °F | 3.58 in. |
| October | 37.1 °F | 57.6 °F | 2.67 in. |
| November | 24.9 °F | 41.5 °F | 1.64 in. |
| December | 13.2 °F | 27.8 °F | 1.21 in. |
| Annual | 34.8 °F | 53.4 °F | 35.14 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 4b : -25°F to -20°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 |