Yamhill, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.5 °C (low) to 17.4 °C (high). Annual precipitation averages 1122.7 Millimeters. Yamhill is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.1 °C | 8.3 °C | 179.58 mm |
| February | 2.2 °C | 10.4 °C | 131.83 mm |
| March | 3.4 °C | 13.1 °C | 128.02 mm |
| April | 5 °C | 15.8 °C | 82.04 mm |
| May | 7.9 °C | 19.9 °C | 51.56 mm |
| June | 10.2 °C | 22.9 °C | 29.46 mm |
| July | 12.3 °C | 27.9 °C | 6.1 mm |
| August | 12.3 °C | 28.2 °C | 9.91 mm |
| September | 10.2 °C | 24.8 °C | 31.75 mm |
| October | 6.8 °C | 17.7 °C | 91.19 mm |
| November | 3.9 °C | 11.5 °C | 168.4 mm |
| December | 1.8 °C | 7.8 °C | 212.85 mm |
| Annual | 6.5 °C | 17.4 °C | 1122.69 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |