Forest Lake, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.5 °C (low) to 12.9 °C (high). Annual precipitation averages 809.5 Millimeters. Forest Lake is located in USDA Plant Hardiness Zone 4b. 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 | -14.9 °C | -4.8 °C | 21.08 mm |
| February | -13.1 °C | -1.8 °C | 20.83 mm |
| March | -6.4 °C | 5.2 °C | 38.1 mm |
| April | 0.8 °C | 13.5 °C | 71.88 mm |
| May | 7.9 °C | 20.6 °C | 105.66 mm |
| June | 13.6 °C | 25.7 °C | 117.35 mm |
| July | 16.1 °C | 28.2 °C | 112.52 mm |
| August | 14.7 °C | 27.1 °C | 102.87 mm |
| September | 10.2 °C | 22.8 °C | 79.76 mm |
| October | 3.2 °C | 14.8 °C | 70.1 mm |
| November | -3.8 °C | 5.7 °C | 40.64 mm |
| December | -10.9 °C | -1.9 °C | 28.7 mm |
| Annual | 1.5 °C | 12.9 °C | 809.49 mm |
| 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 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |