Baytown, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 16.6 °C (low) to 25.4 °C (high). Annual precipitation averages 1512.6 Millimeters. Baytown is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.1 °C | 16.8 °C | 117.6 mm |
| February | 9.2 °C | 18.6 °C | 89.15 mm |
| March | 12.7 °C | 21.7 °C | 95.5 mm |
| April | 16.4 °C | 24.8 °C | 110.49 mm |
| May | 20.6 °C | 28.3 °C | 141.73 mm |
| June | 23.8 °C | 31.5 °C | 152.65 mm |
| July | 24.8 °C | 32.6 °C | 118.87 mm |
| August | 24.6 °C | 33.1 °C | 162.31 mm |
| September | 22.2 °C | 30.8 °C | 144.78 mm |
| October | 17.5 °C | 26.8 °C | 142.49 mm |
| November | 11.9 °C | 21.7 °C | 121.92 mm |
| December | 8.2 °C | 17.8 °C | 115.06 mm |
| Annual | 16.6 °C | 25.4 °C | 1512.55 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 |