Dean, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.7 °C (low) to 24.4 °C (high). Annual precipitation averages 785.1 Millimeters. Dean is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.1 °C | 12.4 °C | 35.05 mm |
| February | 0.7 °C | 14.8 °C | 42.42 mm |
| March | 5.3 °C | 19.6 °C | 61.47 mm |
| April | 9.7 °C | 24.2 °C | 73.66 mm |
| May | 15.6 °C | 28.6 °C | 104.39 mm |
| June | 20.3 °C | 33.2 °C | 92.71 mm |
| July | 22.4 °C | 35.9 °C | 57.4 mm |
| August | 21.9 °C | 35.8 °C | 62.48 mm |
| September | 17.6 °C | 31.3 °C | 77.22 mm |
| October | 11 °C | 25.4 °C | 81.03 mm |
| November | 4.8 °C | 18.6 °C | 51.82 mm |
| December | -0.2 °C | 13.1 °C | 45.47 mm |
| Annual | 10.7 °C | 24.4 °C | 785.12 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |