Tomball, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 15.1 °C (low) to 26.3 °C (high). Annual precipitation averages 1293.6 Millimeters. Tomball is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 21 - Dec. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.6 °C | 16.9 °C | 99.82 mm |
| February | 7.7 °C | 18.9 °C | 84.84 mm |
| March | 11.2 °C | 22.5 °C | 87.63 mm |
| April | 14.8 °C | 26 °C | 94.23 mm |
| May | 19.3 °C | 29.7 °C | 131.06 mm |
| June | 22.6 °C | 32.8 °C | 128.27 mm |
| July | 23.6 °C | 34.1 °C | 95.5 mm |
| August | 23.3 °C | 34.6 °C | 120.65 mm |
| September | 20.7 °C | 32.1 °C | 115.06 mm |
| October | 15.4 °C | 27.7 °C | 121.67 mm |
| November | 10.1 °C | 22.1 °C | 113.79 mm |
| December | 6.4 °C | 17.8 °C | 101.09 mm |
| Annual | 15.1 °C | 26.3 °C | 1293.61 mm |
| Average First Frost Date | Dec. 21 - Dec. 31 |
| Average Last Frost Date | Feb. 1 - Feb. 10 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |