Eureka, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.1 °C (low) to 25 °C (high). Annual precipitation averages 1091.4 Millimeters. Eureka is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.6 °C | 14.4 °C | 83.31 mm |
| February | 4.4 °C | 16.4 °C | 84.58 mm |
| March | 8.5 °C | 20.4 °C | 101.6 mm |
| April | 12.1 °C | 24.6 °C | 97.03 mm |
| May | 17.7 °C | 28.6 °C | 112.01 mm |
| June | 21.7 °C | 32.5 °C | 100.84 mm |
| July | 23.2 °C | 34.7 °C | 52.83 mm |
| August | 23 °C | 35.3 °C | 62.74 mm |
| September | 19.5 °C | 31.9 °C | 81.28 mm |
| October | 13.4 °C | 26.3 °C | 131.06 mm |
| November | 7.7 °C | 19.9 °C | 87.12 mm |
| December | 3.6 °C | 15.3 °C | 97.03 mm |
| Annual | 13.1 °C | 25 °C | 1091.43 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |