Lake Arthur, Louisiana has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 59.2 °F (low) to 77.5 °F (high). Annual precipitation averages 61.8 Inches. Lake Arthur is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 11 - Dec. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 42.1 °F | 60.5 °F | 5.95 in. |
| February | 45.7 °F | 64.3 °F | 4.25 in. |
| March | 52.0 °F | 70.9 °F | 3.54 in. |
| April | 58.9 °F | 77.1 °F | 4.86 in. |
| May | 67.0 °F | 83.9 °F | 5.12 in. |
| June | 72.9 °F | 89.1 °F | 6.5 in. |
| July | 74.6 °F | 90.7 °F | 5.72 in. |
| August | 74.0 °F | 91.4 °F | 6.14 in. |
| September | 69.7 °F | 88.0 °F | 5.48 in. |
| October | 59.5 °F | 80.6 °F | 4.64 in. |
| November | 49.8 °F | 70.3 °F | 5.0 in. |
| December | 44.1 °F | 62.8 °F | 4.64 in. |
| Annual | 59.2 °F | 77.5 °F | 61.84 in. |
| Average First Frost Date | Dec. 11 - Dec. 20 |
| Average Last Frost Date | Feb. 1 - Feb. 10 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |