Edgar, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.5 °C (low) to 16 °C (high). Annual precipitation averages 319 Millimeters. Edgar is located in USDA Plant Hardiness Zone 5a. 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 | -10.1 °C | 2.8 °C | 7.62 mm |
| February | -9 °C | 4.7 °C | 11.94 mm |
| March | -4.6 °C | 10.6 °C | 14.48 mm |
| April | -0.2 °C | 14.9 °C | 42.16 mm |
| May | 4.9 °C | 20.1 °C | 61.72 mm |
| June | 9.4 °C | 25.5 °C | 44.7 mm |
| July | 12.6 °C | 31.2 °C | 22.35 mm |
| August | 11.3 °C | 30.4 °C | 21.08 mm |
| September | 6.4 °C | 24.5 °C | 32.26 mm |
| October | 0.3 °C | 16.1 °C | 34.04 mm |
| November | -5.2 °C | 8.6 °C | 13.21 mm |
| December | -9.7 °C | 2.9 °C | 13.46 mm |
| Annual | 0.5 °C | 16 °C | 319.02 mm |
| 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |