Bonham, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.3 °C (low) to 23.5 °C (high). Annual precipitation averages 1145 Millimeters. Bonham is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0 °C | 11.9 °C | 69.34 mm |
| February | 2 °C | 14.2 °C | 80.52 mm |
| March | 6.2 °C | 18.5 °C | 102.62 mm |
| April | 10.4 °C | 22.8 °C | 98.55 mm |
| May | 15.9 °C | 26.9 °C | 138.94 mm |
| June | 20.5 °C | 31.6 °C | 106.43 mm |
| July | 22.6 °C | 34.3 °C | 71.88 mm |
| August | 21.9 °C | 34.5 °C | 69.85 mm |
| September | 17.9 °C | 30.8 °C | 100.84 mm |
| October | 11.5 °C | 24.9 °C | 112.52 mm |
| November | 5.7 °C | 18.2 °C | 95.5 mm |
| December | 1.3 °C | 13.1 °C | 98.04 mm |
| Annual | 11.3 °C | 23.5 °C | 1145.03 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |