Byram, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.1 °C (low) to 24.5 °C (high). Annual precipitation averages 1476.8 Millimeters. Byram 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. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.2 °C | 13.9 °C | 139.45 mm |
| February | 3.8 °C | 16.5 °C | 141.99 mm |
| March | 7.5 °C | 20.7 °C | 140.46 mm |
| April | 11.6 °C | 24.6 °C | 154.94 mm |
| May | 16.6 °C | 28.6 °C | 108.97 mm |
| June | 20.5 °C | 31.9 °C | 117.35 mm |
| July | 21.8 °C | 33.2 °C | 128.27 mm |
| August | 21.4 °C | 33.3 °C | 115.32 mm |
| September | 18.3 °C | 30.9 °C | 94.49 mm |
| October | 11.7 °C | 25.9 °C | 84.84 mm |
| November | 6.2 °C | 19.6 °C | 117.86 mm |
| December | 3.4 °C | 15.2 °C | 132.84 mm |
| Annual | 12.1 °C | 24.5 °C | 1476.78 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 30-40 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |