Harbor, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 8.3 °C (low) to 16 °C (high). Annual precipitation averages 2007.6 Millimeters. Harbor is located in USDA Plant Hardiness Zone 10a. The growing season typically runs from the last frost around Jan. 21 - Jan. 31 through the first frost around Jan. 1 - Jan. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.1 °C | 12.4 °C | 323.6 mm |
| February | 6 °C | 13.1 °C | 246.63 mm |
| March | 6.1 °C | 13.7 °C | 264.92 mm |
| April | 6.9 °C | 14.8 °C | 188.72 mm |
| May | 8.6 °C | 16.8 °C | 90.17 mm |
| June | 10 °C | 18.5 °C | 55.37 mm |
| July | 11.3 °C | 19.4 °C | 9.4 mm |
| August | 11.6 °C | 19.1 °C | 14.22 mm |
| September | 10.7 °C | 19.8 °C | 37.08 mm |
| October | 9.3 °C | 17.9 °C | 137.41 mm |
| November | 7.5 °C | 14.2 °C | 271.02 mm |
| December | 5.9 °C | 12.3 °C | 369.06 mm |
| Annual | 8.3 °C | 16 °C | 2007.6 mm |
| Average First Frost Date | Jan. 1 - Jan. 10 |
| Average Last Frost Date | Jan. 21 - Jan. 31 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |