Picayune, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.4 °C (low) to 25.4 °C (high). Annual precipitation averages 1665.2 Millimeters. Picayune is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4.1 °C | 16.4 °C | 142.75 mm |
| February | 5.8 °C | 18.4 °C | 117.86 mm |
| March | 9.3 °C | 22.1 °C | 131.83 mm |
| April | 12.7 °C | 25.3 °C | 140.46 mm |
| May | 17.2 °C | 29.2 °C | 136.91 mm |
| June | 21.1 °C | 32 °C | 170.18 mm |
| July | 22.2 °C | 32.8 °C | 194.31 mm |
| August | 22.1 °C | 32.8 °C | 157.73 mm |
| September | 19.8 °C | 30.8 °C | 129.54 mm |
| October | 13.6 °C | 26.7 °C | 100.84 mm |
| November | 7.9 °C | 21.3 °C | 108.71 mm |
| December | 5.2 °C | 17.4 °C | 134.11 mm |
| Annual | 13.4 °C | 25.4 °C | 1665.23 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |