Lostine, Oregon has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Annual precipitation averages 383.6 Millimeters. Lostine is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.7 °C | 2.3 °C | 25.91 mm |
| February | -5.8 °C | 5.7 °C | 27.69 mm |
| March | -3 °C | 10.2 °C | 38.86 mm |
| April | -0.7 °C | 14.1 °C | 35.31 mm |
| May | 2.9 °C | 19.1 °C | 57.91 mm |
| June | 5.7 °C | 22.9 °C | 44.7 mm |
| July | 8.1 °C | 29.2 °C | 13.97 mm |
| August | 7.5 °C | 29.7 °C | 22.35 mm |
| September | 3.7 °C | 24.6 °C | 19.56 mm |
| October | -0.4 °C | 16.4 °C | 30.23 mm |
| November | -4.1 °C | 7.7 °C | 34.29 mm |
| December | -6.9 °C | 2.2 °C | 32.77 mm |
| Annual | 0 °C | 15.3 °C | 383.55 mm |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |