Galliano, Louisiana has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 16.2 °C (low) to 25.5 °C (high). Annual precipitation averages 1649.7 Millimeters. Galliano is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.8 °C | 17.2 °C | 138.43 mm |
| February | 8.9 °C | 19.1 °C | 95.76 mm |
| March | 12.1 °C | 22.1 °C | 105.92 mm |
| April | 16 °C | 25.2 °C | 122.68 mm |
| May | 20.2 °C | 28.8 °C | 121.67 mm |
| June | 22.9 °C | 31.4 °C | 196.09 mm |
| July | 23.6 °C | 32.2 °C | 197.87 mm |
| August | 23.8 °C | 32.4 °C | 200.91 mm |
| September | 22.2 °C | 30.6 °C | 162.56 mm |
| October | 17.7 °C | 26.8 °C | 111.51 mm |
| November | 11.9 °C | 21.9 °C | 86.87 mm |
| December | 8.4 °C | 18.3 °C | 109.47 mm |
| Annual | 16.2 °C | 25.5 °C | 1649.74 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 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |