Yarnell, Arizona has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 46.8 °F (low) to 73 °F (high). Annual precipitation averages 21.8 Inches. Yarnell is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Jan. 21 - Jan. 31 through the first frost around Jan. 21 - Jan. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 32.4 °F | 55.8 °F | 2.21 in. |
| February | 34.0 °F | 57.5 °F | 3.03 in. |
| March | 36.8 °F | 62.8 °F | 2.18 in. |
| April | 42.1 °F | 69.7 °F | 0.71 in. |
| May | 49.8 °F | 78.5 °F | 0.29 in. |
| June | 58.8 °F | 88.8 °F | 0.19 in. |
| July | 65.5 °F | 92.1 °F | 2.28 in. |
| August | 64.4 °F | 90.3 °F | 4.07 in. |
| September | 59.0 °F | 85.6 °F | 2.74 in. |
| October | 48.8 °F | 75.6 °F | 0.85 in. |
| November | 38.3 °F | 63.9 °F | 1.28 in. |
| December | 32.1 °F | 54.9 °F | 2.01 in. |
| Annual | 46.8 °F | 73 °F | 21.84 in. |
| Average First Frost Date | Jan. 21 - Jan. 31 |
| Average Last Frost Date | Jan. 21 - Jan. 31 |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |