Idalou, Texas has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 46.7 °F (low) to 74.5 °F (high). Annual precipitation averages 18.9 Inches. Idalou is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 26.3 °F | 54.4 °F | 0.67 in. |
| February | 29.4 °F | 58.9 °F | 0.7 in. |
| March | 36.8 °F | 67.1 °F | 1.12 in. |
| April | 44.6 °F | 75.6 °F | 1.37 in. |
| May | 55.2 °F | 83.4 °F | 2.6 in. |
| June | 64.3 °F | 90.8 °F | 2.74 in. |
| July | 67.7 °F | 92.8 °F | 2.1 in. |
| August | 66.2 °F | 91.8 °F | 2.0 in. |
| September | 58.9 °F | 84.6 °F | 2.58 in. |
| October | 47.4 °F | 75.5 °F | 1.45 in. |
| November | 35.6 °F | 63.8 °F | 0.89 in. |
| December | 27.9 °F | 55.2 °F | 0.72 in. |
| Annual | 46.7 °F | 74.5 °F | 18.94 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |