Scappoose, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.5 °C (low) to 17.2 °C (high). Annual precipitation averages 1102.4 Millimeters. Scappoose 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. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.8 °C | 8.1 °C | 164.59 mm |
| February | 1.8 °C | 10.3 °C | 118.36 mm |
| March | 3.3 °C | 13.1 °C | 126.75 mm |
| April | 4.9 °C | 16.1 °C | 88.65 mm |
| May | 8.1 °C | 20 °C | 61.47 mm |
| June | 10.4 °C | 22.7 °C | 37.34 mm |
| July | 12.8 °C | 27 °C | 11.18 mm |
| August | 12.8 °C | 27.7 °C | 13.21 mm |
| September | 10.3 °C | 24.4 °C | 38.35 mm |
| October | 6.7 °C | 17.6 °C | 91.95 mm |
| November | 3.8 °C | 11.4 °C | 162.31 mm |
| December | 1.7 °C | 7.7 °C | 188.21 mm |
| Annual | 6.5 °C | 17.2 °C | 1102.37 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |