Brownsville, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.9 °C (low) to 17.7 °C (high). Annual precipitation averages 1041.7 Millimeters. Brownsville is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.7 °C | 8.6 °C | 141.48 mm |
| February | 1.8 °C | 10.7 °C | 113.79 mm |
| March | 3 °C | 13.3 °C | 117.09 mm |
| April | 4.6 °C | 16.2 °C | 91.95 mm |
| May | 7.2 °C | 20 °C | 68.58 mm |
| June | 9.5 °C | 23.1 °C | 40.39 mm |
| July | 11.6 °C | 28.4 °C | 10.67 mm |
| August | 11.3 °C | 28.8 °C | 13.46 mm |
| September | 9.2 °C | 25.3 °C | 39.37 mm |
| October | 6.1 °C | 18.2 °C | 87.63 mm |
| November | 3.6 °C | 11.7 °C | 150.37 mm |
| December | 1.5 °C | 8.1 °C | 166.88 mm |
| Annual | 5.9 °C | 17.7 °C | 1041.66 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 30-40 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 | Severe Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |