Bay City, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.2 °F (low) to 58.3 °F (high). Annual precipitation averages 88 Inches. Bay City is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.8 °F | 50.3 °F | 12.49 in. |
| February | 38.5 °F | 51.7 °F | 9.41 in. |
| March | 39.3 °F | 53.5 °F | 9.77 in. |
| April | 41.1 °F | 55.9 °F | 7.45 in. |
| May | 45.4 °F | 59.7 °F | 4.53 in. |
| June | 49.3 °F | 63.0 °F | 3.26 in. |
| July | 51.8 °F | 66.5 °F | 0.97 in. |
| August | 51.9 °F | 67.4 °F | 1.3 in. |
| September | 49.2 °F | 66.6 °F | 3.11 in. |
| October | 45.4 °F | 60.8 °F | 8.0 in. |
| November | 41.4 °F | 54.2 °F | 13.08 in. |
| December | 38.5 °F | 49.6 °F | 14.64 in. |
| Annual | 44.2 °F | 58.3 °F | 88.01 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |