John Day, Oregon has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 1.2 °C (low) to 17.3 °C (high). Annual precipitation averages 319.5 Millimeters. John Day is located in USDA Plant Hardiness Zone 6b. 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 | -4.9 °C | 5.7 °C | 25.65 mm |
| February | -4.2 °C | 8.1 °C | 17.27 mm |
| March | -2.1 °C | 11.8 °C | 31.75 mm |
| April | 0.1 °C | 15.2 °C | 37.85 mm |
| May | 3.6 °C | 20.2 °C | 48.77 mm |
| June | 6.7 °C | 24.7 °C | 34.04 mm |
| July | 9.4 °C | 31.5 °C | 12.19 mm |
| August | 8.6 °C | 31.2 °C | 12.19 mm |
| September | 4.7 °C | 26.2 °C | 11.94 mm |
| October | 0.4 °C | 18.1 °C | 28.19 mm |
| November | -2.7 °C | 9.7 °C | 30.73 mm |
| December | -5.4 °C | 4.7 °C | 28.96 mm |
| Annual | 1.2 °C | 17.3 °C | 319.53 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |