Dallas, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.8 °C (low) to 17.4 °C (high). Annual precipitation averages 1289.1 Millimeters. Dallas is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.6 °C | 8.2 °C | 207.52 mm |
| February | 1.7 °C | 10.4 °C | 153.42 mm |
| March | 2.8 °C | 13 °C | 145.8 mm |
| April | 4.3 °C | 15.8 °C | 102.36 mm |
| May | 7.1 °C | 19.8 °C | 55.88 mm |
| June | 9.3 °C | 22.8 °C | 36.07 mm |
| July | 11.2 °C | 27.8 °C | 7.11 mm |
| August | 11.2 °C | 28.2 °C | 9.4 mm |
| September | 9.4 °C | 25.1 °C | 38.1 mm |
| October | 6.2 °C | 18 °C | 101.09 mm |
| November | 3.4 °C | 11.4 °C | 181.1 mm |
| December | 1.3 °C | 7.7 °C | 251.21 mm |
| Annual | 5.8 °C | 17.4 °C | 1289.06 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 40-50 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 | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |