Hartland, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 44.7 °F (low) to 66 °F (high). Annual precipitation averages 32 Inches. Hartland is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 33.9 °F | 52.0 °F | 6.13 in. |
| February | 33.2 °F | 51.2 °F | 5.81 in. |
| March | 35.8 °F | 54.7 °F | 5.18 in. |
| April | 38.8 °F | 58.5 °F | 2.85 in. |
| May | 46.1 °F | 67.5 °F | 1.39 in. |
| June | 53.9 °F | 78.0 °F | 0.46 in. |
| July | 60.6 °F | 85.6 °F | 0.18 in. |
| August | 59.8 °F | 85.6 °F | 0.09 in. |
| September | 55.6 °F | 80.1 °F | 0.22 in. |
| October | 46.4 °F | 69.4 °F | 1.55 in. |
| November | 38.9 °F | 58.5 °F | 2.85 in. |
| December | 33.6 °F | 51.1 °F | 5.26 in. |
| Annual | 44.7 °F | 66 °F | 31.97 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |