Tumalo, Oregon has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 0.8 °C (low) to 16.5 °C (high). Annual precipitation averages 310.7 Millimeters. Tumalo is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.2 °C | 6.1 °C | 40.13 mm |
| February | -4.1 °C | 7.9 °C | 33.53 mm |
| March | -2.6 °C | 11.4 °C | 19.56 mm |
| April | -1 °C | 14.4 °C | 22.1 mm |
| May | 2.5 °C | 19.3 °C | 29.72 mm |
| June | 5.3 °C | 23.4 °C | 25.65 mm |
| July | 8.4 °C | 29.2 °C | 16.51 mm |
| August | 8.2 °C | 29 °C | 14.48 mm |
| September | 4.5 °C | 24.6 °C | 9.65 mm |
| October | 0.4 °C | 17.4 °C | 16.26 mm |
| November | -2.6 °C | 9.7 °C | 41.66 mm |
| December | -5 °C | 5.2 °C | 41.4 mm |
| Annual | 0.8 °C | 16.5 °C | 310.65 mm |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | May 21 - May 31 |
| 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 | Dsb - Humid Continental Climate - Dry Cool Summer |