Smithfield, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 51.7 °F (low) to 69.2 °F (high). Annual precipitation averages 49.4 Inches. Smithfield is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 31.8 °F | 48.8 °F | 3.51 in. |
| February | 33.5 °F | 51.6 °F | 2.87 in. |
| March | 40.0 °F | 58.6 °F | 4.08 in. |
| April | 49.7 °F | 69.2 °F | 3.69 in. |
| May | 59.1 °F | 76.7 °F | 4.08 in. |
| June | 67.7 °F | 84.5 °F | 4.44 in. |
| July | 72.0 °F | 88.5 °F | 4.86 in. |
| August | 70.7 °F | 86.5 °F | 5.65 in. |
| September | 65.0 °F | 81.1 °F | 5.37 in. |
| October | 53.3 °F | 71.2 °F | 3.83 in. |
| November | 42.5 °F | 61.1 °F | 3.33 in. |
| December | 35.5 °F | 52.7 °F | 3.69 in. |
| Annual | 51.7 °F | 69.2 °F | 49.4 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |