Oceano, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 49.8 °F (low) to 67.4 °F (high). Annual precipitation averages 15.2 Inches. Oceano is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 45.9 °F | 64.2 °F | 2.91 in. |
| February | 46.2 °F | 64.2 °F | 3.38 in. |
| March | 47.0 °F | 65.3 °F | 2.77 in. |
| April | 47.8 °F | 68.1 °F | 0.89 in. |
| May | 49.6 °F | 67.6 °F | 0.42 in. |
| June | 52.0 °F | 70.3 °F | 0.08 in. |
| July | 54.7 °F | 70.4 °F | 0.06 in. |
| August | 54.7 °F | 67.7 °F | 0.02 in. |
| September | 53.5 °F | 68.7 °F | 0.08 in. |
| October | 51.7 °F | 69.4 °F | 0.69 in. |
| November | 48.9 °F | 68.4 °F | 1.4 in. |
| December | 45.2 °F | 64.0 °F | 2.5 in. |
| Annual | 49.8 °F | 67.4 °F | 15.2 in. |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 10a : 30°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 10a : 30°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |