Cullen, Louisiana has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.7 °C (low) to 24.3 °C (high). Annual precipitation averages 1376.9 Millimeters. Cullen is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.3 °C | 13.4 °C | 116.59 mm |
| February | 2.9 °C | 15.6 °C | 119.63 mm |
| March | 6.6 °C | 20.1 °C | 140.97 mm |
| April | 10.8 °C | 24.3 °C | 127.76 mm |
| May | 16.2 °C | 28.4 °C | 124.71 mm |
| June | 20.6 °C | 32.1 °C | 111 mm |
| July | 22.2 °C | 33.9 °C | 99.31 mm |
| August | 21.7 °C | 34.2 °C | 83.31 mm |
| September | 18.1 °C | 31.1 °C | 94.74 mm |
| October | 11.3 °C | 25.2 °C | 125.22 mm |
| November | 5.8 °C | 18.9 °C | 104.14 mm |
| December | 2.3 °C | 14.4 °C | 129.54 mm |
| Annual | 11.7 °C | 24.3 °C | 1376.92 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 50-75 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 |