Grayson, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 48.3 °F (low) to 73.7 °F (high). Annual precipitation averages 11.6 Inches. Grayson is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.5 °F | 55.2 °F | 2.42 in. |
| February | 40.8 °F | 61.0 °F | 2.08 in. |
| March | 43.4 °F | 66.5 °F | 1.69 in. |
| April | 46.5 °F | 71.2 °F | 0.91 in. |
| May | 51.4 °F | 79.0 °F | 0.58 in. |
| June | 56.1 °F | 86.4 °F | 0.09 in. |
| July | 59.0 °F | 91.1 °F | 0.0 in. |
| August | 58.4 °F | 89.8 °F | 0.02 in. |
| September | 55.6 °F | 86.2 °F | 0.08 in. |
| October | 49.6 °F | 77.2 °F | 0.59 in. |
| November | 42.2 °F | 65.2 °F | 1.03 in. |
| December | 38.1 °F | 55.8 °F | 2.07 in. |
| Annual | 48.3 °F | 73.7 °F | 11.56 in. |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 1 - Feb. 10 |
| Average Days With Frost | 10-20 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 |