Lake Arthur, Louisiana has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 15.1 °C (low) to 25.3 °C (high). Annual precipitation averages 1570.8 Millimeters. 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 | 5.6 °C | 15.8 °C | 151.13 mm |
| February | 7.6 °C | 17.9 °C | 107.95 mm |
| March | 11.1 °C | 21.6 °C | 89.92 mm |
| April | 14.9 °C | 25.1 °C | 123.44 mm |
| May | 19.4 °C | 28.8 °C | 130.05 mm |
| June | 22.7 °C | 31.7 °C | 165.1 mm |
| July | 23.7 °C | 32.6 °C | 145.29 mm |
| August | 23.3 °C | 33 °C | 155.96 mm |
| September | 20.9 °C | 31.1 °C | 139.19 mm |
| October | 15.3 °C | 27 °C | 117.86 mm |
| November | 9.9 °C | 21.3 °C | 127 mm |
| December | 6.7 °C | 17.1 °C | 117.86 mm |
| Annual | 15.1 °C | 25.3 °C | 1570.75 mm |
| 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 : -6.7°C to -3.9°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 |