Washington, Louisiana has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 57.5 °F (low) to 77.9 °F (high). Annual precipitation averages 62.9 Inches. Washington is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 40.7 °F | 61.0 °F | 6.75 in. |
| February | 44.2 °F | 64.8 °F | 4.9 in. |
| March | 50.4 °F | 71.8 °F | 4.31 in. |
| April | 56.8 °F | 77.9 °F | 5.04 in. |
| May | 65.3 °F | 84.7 °F | 5.36 in. |
| June | 71.4 °F | 89.7 °F | 6.07 in. |
| July | 73.2 °F | 91.1 °F | 5.23 in. |
| August | 72.5 °F | 91.9 °F | 5.36 in. |
| September | 67.8 °F | 88.2 °F | 5.04 in. |
| October | 57.3 °F | 80.4 °F | 4.8 in. |
| November | 47.6 °F | 70.3 °F | 4.91 in. |
| December | 42.6 °F | 63.1 °F | 5.17 in. |
| Annual | 57.5 °F | 77.9 °F | 62.94 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| 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 |