O'Donnell, Texas has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 8.5 °C (low) to 23.9 °C (high). Annual precipitation averages 478.8 Millimeters. O'Donnell is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.7 °C | 13 °C | 17.78 mm |
| February | -1 °C | 15.5 °C | 18.8 mm |
| March | 3.1 °C | 20 °C | 27.43 mm |
| April | 7.4 °C | 24.6 °C | 31.5 mm |
| May | 13.2 °C | 28.9 °C | 66.55 mm |
| June | 18.2 °C | 32.7 °C | 64.01 mm |
| July | 19.9 °C | 33.8 °C | 48.51 mm |
| August | 19.2 °C | 33.3 °C | 49.28 mm |
| September | 15.3 °C | 29.1 °C | 69.6 mm |
| October | 9.1 °C | 24.6 °C | 39.88 mm |
| November | 2.3 °C | 18 °C | 25.65 mm |
| December | -1.7 °C | 13.5 °C | 19.81 mm |
| Annual | 8.5 °C | 23.9 °C | 478.8 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |