Porterville, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 50.1 °F (low) to 77.7 °F (high). Annual precipitation averages 10.8 Inches. Porterville is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.1 °F | 57.5 °F | 2.13 in. |
| February | 40.5 °F | 62.9 °F | 1.81 in. |
| March | 43.8 °F | 69.0 °F | 1.83 in. |
| April | 47.0 °F | 75.0 °F | 1.06 in. |
| May | 53.4 °F | 83.8 °F | 0.45 in. |
| June | 59.4 °F | 92.3 °F | 0.1 in. |
| July | 65.3 °F | 97.6 °F | 0.04 in. |
| August | 63.9 °F | 96.7 °F | 0.04 in. |
| September | 59.3 °F | 92.0 °F | 0.06 in. |
| October | 50.9 °F | 80.8 °F | 0.53 in. |
| November | 42.2 °F | 66.9 °F | 0.91 in. |
| December | 36.8 °F | 57.4 °F | 1.79 in. |
| Annual | 50.1 °F | 77.7 °F | 10.75 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |