Porterville, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 10 °C (low) to 25.4 °C (high). Annual precipitation averages 273 Millimeters. 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 | 3.4 °C | 14.2 °C | 54.1 mm |
| February | 4.7 °C | 17.2 °C | 45.97 mm |
| March | 6.6 °C | 20.6 °C | 46.48 mm |
| April | 8.3 °C | 23.9 °C | 26.92 mm |
| May | 11.9 °C | 28.8 °C | 11.43 mm |
| June | 15.2 °C | 33.5 °C | 2.54 mm |
| July | 18.5 °C | 36.4 °C | 1.02 mm |
| August | 17.7 °C | 35.9 °C | 1.02 mm |
| September | 15.2 °C | 33.3 °C | 1.52 mm |
| October | 10.5 °C | 27.1 °C | 13.46 mm |
| November | 5.7 °C | 19.4 °C | 23.11 mm |
| December | 2.7 °C | 14.1 °C | 45.47 mm |
| Annual | 10 °C | 25.4 °C | 273.04 mm |
| 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 : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |