Lakeside, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.8 °C (low) to 13.3 °C (high). Annual precipitation averages 413.5 Millimeters. Lakeside is located in USDA Plant Hardiness Zone 5b. 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 | -7.2 °C | 0.3 °C | 31.24 mm |
| February | -6.8 °C | 2.3 °C | 24.38 mm |
| March | -3.6 °C | 7.3 °C | 27.18 mm |
| April | -0.1 °C | 12.9 °C | 38.61 mm |
| May | 4.2 °C | 18.5 °C | 42.93 mm |
| June | 7.8 °C | 22 °C | 66.55 mm |
| July | 10.2 °C | 28.1 °C | 29.72 mm |
| August | 9.3 °C | 28 °C | 22.61 mm |
| September | 5.3 °C | 21.9 °C | 29.97 mm |
| October | 0.4 °C | 13.2 °C | 37.59 mm |
| November | -3.3 °C | 5.1 °C | 31.5 mm |
| December | -6.6 °C | 0.3 °C | 31.24 mm |
| Annual | 0.8 °C | 13.3 °C | 413.52 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |