Coos Bay, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.3 °C (low) to 15.5 °C (high). Annual precipitation averages 1616.2 Millimeters. Coos Bay is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Frost Rare through the first frost around Jan. 21 - Jan. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4.4 °C | 11.8 °C | 249.17 mm |
| February | 4.3 °C | 12.3 °C | 191.01 mm |
| March | 4.8 °C | 12.8 °C | 196.85 mm |
| April | 5.9 °C | 14.1 °C | 141.99 mm |
| May | 8.1 °C | 16 °C | 90.68 mm |
| June | 10.1 °C | 17.9 °C | 48.77 mm |
| July | 11.3 °C | 18.9 °C | 10.41 mm |
| August | 11.2 °C | 19.7 °C | 12.45 mm |
| September | 9.9 °C | 19.7 °C | 42.93 mm |
| October | 8.1 °C | 17.3 °C | 117.09 mm |
| November | 5.8 °C | 13.8 °C | 218.44 mm |
| December | 4.2 °C | 11.4 °C | 296.42 mm |
| Annual | 7.3 °C | 15.5 °C | 1616.21 mm |
| Average First Frost Date | Jan. 21 - Jan. 31 |
| Average Last Frost Date | Frost Rare |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9b : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |