Calvert, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 56.7 °F (low) to 78.8 °F (high). Annual precipitation averages 39.4 Inches. Calvert is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.6 °F | 60.4 °F | 3.35 in. |
| February | 42.2 °F | 64.1 °F | 2.82 in. |
| March | 48.5 °F | 71.0 °F | 3.37 in. |
| April | 55.6 °F | 78.4 °F | 3.0 in. |
| May | 64.7 °F | 85.2 °F | 4.53 in. |
| June | 71.5 °F | 91.7 °F | 3.38 in. |
| July | 73.6 °F | 95.1 °F | 1.83 in. |
| August | 73.0 °F | 96.1 °F | 2.65 in. |
| September | 67.5 °F | 90.5 °F | 3.35 in. |
| October | 57.4 °F | 81.2 °F | 4.32 in. |
| November | 47.4 °F | 70.1 °F | 3.19 in. |
| December | 40.2 °F | 62.0 °F | 3.59 in. |
| Annual | 56.7 °F | 78.8 °F | 39.38 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |