Pasadena, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 16.5 °C (low) to 26.1 °C (high). Annual precipitation averages 1450.1 Millimeters. Pasadena is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.2 °C | 17.2 °C | 108.71 mm |
| February | 9.2 °C | 19.1 °C | 81.79 mm |
| March | 12.8 °C | 22.2 °C | 93.22 mm |
| April | 16.3 °C | 25.7 °C | 106.43 mm |
| May | 20.5 °C | 29.3 °C | 134.62 mm |
| June | 23.8 °C | 32.4 °C | 153.92 mm |
| July | 24.7 °C | 33.4 °C | 116.33 mm |
| August | 24.6 °C | 33.9 °C | 145.29 mm |
| September | 22.3 °C | 31.6 °C | 145.8 mm |
| October | 17.2 °C | 27.6 °C | 134.11 mm |
| November | 11.7 °C | 22.1 °C | 118.36 mm |
| December | 8.2 °C | 18.2 °C | 111.51 mm |
| Annual | 16.5 °C | 26.1 °C | 1450.09 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 |