West Linn, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.3 °C (low) to 17.6 °C (high). Annual precipitation averages 1096.3 Millimeters. West Linn 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 | 2.4 °C | 8.4 °C | 158.5 mm |
| February | 2.7 °C | 10.7 °C | 110.49 mm |
| March | 4.1 °C | 13.5 °C | 121.92 mm |
| April | 5.9 °C | 16.4 °C | 93.22 mm |
| May | 8.9 °C | 20.5 °C | 61.47 mm |
| June | 11.3 °C | 23.3 °C | 41.4 mm |
| July | 13.4 °C | 27.7 °C | 10.16 mm |
| August | 13.5 °C | 28 °C | 14.73 mm |
| September | 11.2 °C | 24.7 °C | 36.32 mm |
| October | 7.7 °C | 18 °C | 97.54 mm |
| November | 4.7 °C | 11.7 °C | 166.62 mm |
| December | 2.3 °C | 8.1 °C | 183.9 mm |
| Annual | 7.3 °C | 17.6 °C | 1096.27 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 |