Phelan, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 6.9 °C (low) to 22.7 °C (high). Annual precipitation averages 350.5 Millimeters. Phelan is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.2 °C | 13.6 °C | 64.26 mm |
| February | 0.6 °C | 14.6 °C | 99.82 mm |
| March | 2.6 °C | 17.8 °C | 40.39 mm |
| April | 4.5 °C | 20.2 °C | 16.26 mm |
| May | 8.2 °C | 24.9 °C | 4.83 mm |
| June | 12.1 °C | 30.3 °C | 3.81 mm |
| July | 15.9 °C | 33.4 °C | 6.35 mm |
| August | 15.2 °C | 33.2 °C | 3.05 mm |
| September | 13.1 °C | 29.6 °C | 5.08 mm |
| October | 7.8 °C | 23.4 °C | 15.24 mm |
| November | 2.8 °C | 18 °C | 22.1 mm |
| December | -0.1 °C | 13 °C | 69.34 mm |
| Annual | 6.9 °C | 22.7 °C | 350.53 mm |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |