Lostine, Oregon has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32 °F (low) to 59.6 °F (high). Annual precipitation averages 15.1 Inches. 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 | 19.9 °F | 36.2 °F | 1.02 in. |
| February | 21.6 °F | 42.3 °F | 1.09 in. |
| March | 26.6 °F | 50.3 °F | 1.53 in. |
| April | 30.8 °F | 57.3 °F | 1.39 in. |
| May | 37.3 °F | 66.4 °F | 2.28 in. |
| June | 42.3 °F | 73.3 °F | 1.76 in. |
| July | 46.5 °F | 84.6 °F | 0.55 in. |
| August | 45.5 °F | 85.4 °F | 0.88 in. |
| September | 38.6 °F | 76.2 °F | 0.77 in. |
| October | 31.2 °F | 61.6 °F | 1.19 in. |
| November | 24.7 °F | 45.8 °F | 1.35 in. |
| December | 19.5 °F | 36.0 °F | 1.29 in. |
| Annual | 32 °F | 59.6 °F | 15.1 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |