Graham, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.1 °C (low) to 25.1 °C (high). Annual precipitation averages 805.7 Millimeters. Graham is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.6 °C | 13.8 °C | 33.78 mm |
| February | 1.3 °C | 15.9 °C | 44.7 mm |
| March | 5.7 °C | 20.6 °C | 65.79 mm |
| April | 10.2 °C | 25.1 °C | 59.69 mm |
| May | 15.9 °C | 29.2 °C | 116.08 mm |
| June | 20.7 °C | 33.3 °C | 92.46 mm |
| July | 22.6 °C | 35.9 °C | 54.61 mm |
| August | 22.2 °C | 36 °C | 62.74 mm |
| September | 17.9 °C | 31.7 °C | 87.12 mm |
| October | 11.4 °C | 26.2 °C | 92.96 mm |
| November | 5.2 °C | 19.6 °C | 50.55 mm |
| December | 0.5 °C | 14.4 °C | 45.21 mm |
| Annual | 11.1 °C | 25.1 °C | 805.69 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |