Crystal City, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 15.5 °C (low) to 29 °C (high). Annual precipitation averages 527 Millimeters. Crystal City is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.5 °C | 19.4 °C | 25.65 mm |
| February | 7.9 °C | 22.3 °C | 22.61 mm |
| March | 11.9 °C | 25.9 °C | 43.94 mm |
| April | 15.6 °C | 29.8 °C | 31.75 mm |
| May | 20.1 °C | 33.1 °C | 76.71 mm |
| June | 23.1 °C | 35.9 °C | 56.13 mm |
| July | 23.8 °C | 36.8 °C | 47.75 mm |
| August | 24 °C | 37.2 °C | 36.32 mm |
| September | 21.3 °C | 33.9 °C | 83.82 mm |
| October | 16.3 °C | 29.8 °C | 48.77 mm |
| November | 10.7 °C | 23.9 °C | 30.48 mm |
| December | 6.2 °C | 19.9 °C | 23.11 mm |
| Annual | 15.5 °C | 29 °C | 527.04 mm |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |