Lamar, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 64.9 °F (low) to 77.9 °F (high). Annual precipitation averages 35.4 Inches. Lamar is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 47.9 °F | 63.4 °F | 2.5 in. |
| February | 51.9 °F | 66.7 °F | 1.89 in. |
| March | 58.1 °F | 71.6 °F | 2.62 in. |
| April | 64.7 °F | 77.1 °F | 2.06 in. |
| May | 72.2 °F | 82.7 °F | 3.39 in. |
| June | 77.5 °F | 87.6 °F | 3.88 in. |
| July | 78.6 °F | 88.5 °F | 2.86 in. |
| August | 78.2 °F | 90.0 °F | 2.53 in. |
| September | 74.5 °F | 87.8 °F | 5.13 in. |
| October | 67.3 °F | 81.2 °F | 3.58 in. |
| November | 57.5 °F | 72.7 °F | 2.9 in. |
| December | 50.1 °F | 65.7 °F | 2.1 in. |
| Annual | 64.9 °F | 77.9 °F | 35.44 in. |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |