Dallas, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42.4 °F (low) to 63.2 °F (high). Annual precipitation averages 50.8 Inches. 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 | 34.8 °F | 46.8 °F | 8.17 in. |
| February | 35.0 °F | 50.7 °F | 6.04 in. |
| March | 37.1 °F | 55.4 °F | 5.74 in. |
| April | 39.7 °F | 60.4 °F | 4.03 in. |
| May | 44.7 °F | 67.6 °F | 2.2 in. |
| June | 48.8 °F | 73.0 °F | 1.42 in. |
| July | 52.2 °F | 82.0 °F | 0.28 in. |
| August | 52.2 °F | 82.8 °F | 0.37 in. |
| September | 49.0 °F | 77.1 °F | 1.5 in. |
| October | 43.2 °F | 64.4 °F | 3.98 in. |
| November | 38.2 °F | 52.5 °F | 7.13 in. |
| December | 34.3 °F | 45.9 °F | 9.89 in. |
| Annual | 42.4 °F | 63.2 °F | 50.75 in. |
| 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 : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |