Opal, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 6.7 °C (low) to 19.3 °C (high). Annual precipitation averages 1170.9 Millimeters. Opal is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.6 °C | 6.9 °C | 78.23 mm |
| February | -3.6 °C | 8.6 °C | 67.82 mm |
| March | 0.2 °C | 13.2 °C | 98.55 mm |
| April | 5.8 °C | 19.6 °C | 92.96 mm |
| May | 11.2 °C | 23.9 °C | 116.08 mm |
| June | 16.1 °C | 28.5 °C | 116.08 mm |
| July | 18.7 °C | 30.9 °C | 113.54 mm |
| August | 17.7 °C | 29.9 °C | 94.49 mm |
| September | 13.7 °C | 26.4 °C | 120.9 mm |
| October | 6.9 °C | 20.3 °C | 98.55 mm |
| November | 1.2 °C | 14.3 °C | 81.79 mm |
| December | -2.4 °C | 8.9 °C | 91.95 mm |
| Annual | 6.7 °C | 19.3 °C | 1170.94 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |