McLean, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.4 °C (low) to 22.2 °C (high). Annual precipitation averages 675.1 Millimeters. McLean is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.2 °C | 10.5 °C | 22.61 mm |
| February | -2.7 °C | 12.6 °C | 23.11 mm |
| March | 1.6 °C | 17.6 °C | 39.88 mm |
| April | 6 °C | 22.3 °C | 62.99 mm |
| May | 11.8 °C | 26.7 °C | 90.68 mm |
| June | 17.2 °C | 31.2 °C | 90.42 mm |
| July | 19.5 °C | 33.7 °C | 79.76 mm |
| August | 18.8 °C | 33 °C | 78.49 mm |
| September | 14.6 °C | 28.8 °C | 61.98 mm |
| October | 7.8 °C | 22.9 °C | 66.55 mm |
| November | 1.2 °C | 16.3 °C | 30.73 mm |
| December | -3.3 °C | 10.8 °C | 27.94 mm |
| Annual | 7.4 °C | 22.2 °C | 675.14 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |