Halfway, Oregon has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 1.6 °C (low) to 17 °C (high). Annual precipitation averages 539.7 Millimeters. Halfway 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 Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.8 °C | 1.8 °C | 89.15 mm |
| February | -5.1 °C | 5.6 °C | 55.63 mm |
| March | -1.7 °C | 11.7 °C | 46.74 mm |
| April | 0.8 °C | 16.6 °C | 39.62 mm |
| May | 4.6 °C | 21.9 °C | 45.47 mm |
| June | 8.1 °C | 26.3 °C | 33.27 mm |
| July | 11.3 °C | 32.6 °C | 11.68 mm |
| August | 10.3 °C | 32.2 °C | 8.38 mm |
| September | 5.8 °C | 26.7 °C | 16.76 mm |
| October | 0.8 °C | 17.8 °C | 33.02 mm |
| November | -3.2 °C | 8.4 °C | 63.75 mm |
| December | -6.3 °C | 2.4 °C | 96.27 mm |
| Annual | 1.6 °C | 17 °C | 539.74 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |