Oregon City, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.1 °F (low) to 63.7 °F (high). Annual precipitation averages 44.3 Inches. Oregon City is located in USDA Plant Hardiness Zone 9a. 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 | 36.3 °F | 47.3 °F | 6.41 in. |
| February | 36.8 °F | 51.2 °F | 4.51 in. |
| March | 39.1 °F | 56.2 °F | 4.86 in. |
| April | 42.5 °F | 61.6 °F | 3.83 in. |
| May | 47.9 °F | 68.8 °F | 2.39 in. |
| June | 52.1 °F | 74.0 °F | 1.65 in. |
| July | 56.1 °F | 81.9 °F | 0.42 in. |
| August | 56.2 °F | 82.4 °F | 0.6 in. |
| September | 51.9 °F | 76.5 °F | 1.5 in. |
| October | 45.7 °F | 64.4 °F | 3.91 in. |
| November | 40.2 °F | 53.1 °F | 6.69 in. |
| December | 36.0 °F | 46.5 °F | 7.5 in. |
| Annual | 45.1 °F | 63.7 °F | 44.27 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| 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 |