West Linn, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.2 °F (low) to 63.7 °F (high). Annual precipitation averages 43.2 Inches. 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 | 36.4 °F | 47.2 °F | 6.24 in. |
| February | 36.9 °F | 51.2 °F | 4.35 in. |
| March | 39.3 °F | 56.3 °F | 4.8 in. |
| April | 42.6 °F | 61.6 °F | 3.67 in. |
| May | 48.0 °F | 68.9 °F | 2.42 in. |
| June | 52.3 °F | 74.0 °F | 1.63 in. |
| July | 56.2 °F | 81.9 °F | 0.4 in. |
| August | 56.3 °F | 82.4 °F | 0.58 in. |
| September | 52.1 °F | 76.5 °F | 1.43 in. |
| October | 45.8 °F | 64.4 °F | 3.84 in. |
| November | 40.4 °F | 53.1 °F | 6.56 in. |
| December | 36.2 °F | 46.5 °F | 7.24 in. |
| Annual | 45.2 °F | 63.7 °F | 43.16 in. |
| 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 : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |