Oceanside, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 11.8 °C (low) to 20.5 °C (high). Annual precipitation averages 270 Millimeters. Oceanside is located in USDA Plant Hardiness Zone 10a. The growing season typically runs from the last frost around Frost Rare through the first frost around Frost Rare.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.9 °C | 18.8 °C | 53.59 mm |
| February | 7.6 °C | 18.4 °C | 62.48 mm |
| March | 8.9 °C | 18.6 °C | 39.62 mm |
| April | 10.2 °C | 18.7 °C | 21.08 mm |
| May | 13.1 °C | 19.5 °C | 7.11 mm |
| June | 15.2 °C | 20.6 °C | 2.29 mm |
| July | 17.2 °C | 22.5 °C | 1.27 mm |
| August | 17.6 °C | 23.4 °C | 0.76 mm |
| September | 16.2 °C | 23.2 °C | 3.81 mm |
| October | 13.2 °C | 22.3 °C | 13.72 mm |
| November | 9.1 °C | 21.3 °C | 19.81 mm |
| December | 6.6 °C | 18.8 °C | 44.45 mm |
| Annual | 11.8 °C | 20.5 °C | 269.99 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | Frost Rare |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 10a : -1.1°C to 1.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |