Hartley, Texas has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 5 °C (low) to 21.3 °C (high). Annual precipitation averages 444.8 Millimeters. Hartley is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.2 °C | 9.8 °C | 12.7 mm |
| February | -4.8 °C | 12 °C | 9.14 mm |
| March | -0.9 °C | 16.7 °C | 25.4 mm |
| April | 3.4 °C | 20.8 °C | 29.46 mm |
| May | 9.3 °C | 25.9 °C | 51.82 mm |
| June | 14.9 °C | 31.1 °C | 69.34 mm |
| July | 17.4 °C | 32.9 °C | 64.26 mm |
| August | 16.7 °C | 31.8 °C | 64.52 mm |
| September | 12.4 °C | 28.2 °C | 38.61 mm |
| October | 5.2 °C | 21.8 °C | 46.23 mm |
| November | -1.4 °C | 15.2 °C | 13.46 mm |
| December | -5.7 °C | 9.7 °C | 19.81 mm |
| Annual | 5 °C | 21.3 °C | 444.75 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |