Galveston, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 18.7 °C (low) to 24.3 °C (high). Annual precipitation averages 1316.2 Millimeters. Galveston is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 9.3 °C | 16.2 °C | 114.81 mm |
| February | 11.1 °C | 17.4 °C | 78.23 mm |
| March | 14.6 °C | 20.3 °C | 84.58 mm |
| April | 18.3 °C | 23.4 °C | 98.81 mm |
| May | 22.5 °C | 26.9 °C | 85.34 mm |
| June | 25.6 °C | 29.9 °C | 111 mm |
| July | 26.7 °C | 31.1 °C | 100.58 mm |
| August | 26.4 °C | 31.4 °C | 136.65 mm |
| September | 24.6 °C | 29.8 °C | 164.59 mm |
| October | 20.6 °C | 26.1 °C | 122.68 mm |
| November | 14.8 °C | 21.2 °C | 112.01 mm |
| December | 10.4 °C | 17.3 °C | 106.93 mm |
| Annual | 18.7 °C | 24.3 °C | 1316.21 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°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 |