Oatfield, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.9 °C (low) to 17.4 °C (high). Annual precipitation averages 1116.6 Millimeters. Oatfield is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.2 °C | 8.5 °C | 164.59 mm |
| February | 2.4 °C | 10.6 °C | 113.54 mm |
| March | 3.7 °C | 13.3 °C | 123.7 mm |
| April | 5.4 °C | 16.2 °C | 94.49 mm |
| May | 8.4 °C | 20.2 °C | 70.1 mm |
| June | 10.7 °C | 23.1 °C | 43.43 mm |
| July | 12.9 °C | 27.5 °C | 11.68 mm |
| August | 13.1 °C | 27.8 °C | 14.73 mm |
| September | 10.8 °C | 24.4 °C | 39.37 mm |
| October | 7.4 °C | 17.6 °C | 98.55 mm |
| November | 4.2 °C | 11.6 °C | 162.56 mm |
| December | 1.9 °C | 8 °C | 179.83 mm |
| Annual | 6.9 °C | 17.4 °C | 1116.57 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°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 |