Idalou, Texas has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 8.2 °C (low) to 23.6 °C (high). Annual precipitation averages 481.1 Millimeters. 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 | -3.2 °C | 12.4 °C | 17.02 mm |
| February | -1.4 °C | 14.9 °C | 17.78 mm |
| March | 2.7 °C | 19.5 °C | 28.45 mm |
| April | 7 °C | 24.2 °C | 34.8 mm |
| May | 12.9 °C | 28.6 °C | 66.04 mm |
| June | 17.9 °C | 32.7 °C | 69.6 mm |
| July | 19.8 °C | 33.8 °C | 53.34 mm |
| August | 19 °C | 33.2 °C | 50.8 mm |
| September | 14.9 °C | 29.2 °C | 65.53 mm |
| October | 8.6 °C | 24.2 °C | 36.83 mm |
| November | 2 °C | 17.7 °C | 22.61 mm |
| December | -2.3 °C | 12.9 °C | 18.29 mm |
| Annual | 8.2 °C | 23.6 °C | 481.09 mm |
| 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 : -15°C to -12.2°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 |