Lamar, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 18.3 °C (low) to 25.5 °C (high). Annual precipitation averages 900.2 Millimeters. Lamar is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.8 °C | 17.4 °C | 63.5 mm |
| February | 11.1 °C | 19.3 °C | 48.01 mm |
| March | 14.5 °C | 22 °C | 66.55 mm |
| April | 18.2 °C | 25.1 °C | 52.32 mm |
| May | 22.3 °C | 28.2 °C | 86.11 mm |
| June | 25.3 °C | 30.9 °C | 98.55 mm |
| July | 25.9 °C | 31.4 °C | 72.64 mm |
| August | 25.7 °C | 32.2 °C | 64.26 mm |
| September | 23.6 °C | 31 °C | 130.3 mm |
| October | 19.6 °C | 27.3 °C | 90.93 mm |
| November | 14.2 °C | 22.6 °C | 73.66 mm |
| December | 10.1 °C | 18.7 °C | 53.34 mm |
| Annual | 18.3 °C | 25.5 °C | 900.17 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9b : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |