Vienna, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.5 °C (low) to 19.9 °C (high). Annual precipitation averages 1147.3 Millimeters. Vienna is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.4 °C | 7.7 °C | 83.31 mm |
| February | -1.9 °C | 9.2 °C | 73.66 mm |
| March | 1.6 °C | 13.2 °C | 102.11 mm |
| April | 7.1 °C | 19.6 °C | 89.15 mm |
| May | 12.4 °C | 24.4 °C | 95 mm |
| June | 17.5 °C | 29.2 °C | 111.25 mm |
| July | 20.2 °C | 31.6 °C | 105.66 mm |
| August | 18.9 °C | 30.3 °C | 117.6 mm |
| September | 15.6 °C | 27.3 °C | 101.85 mm |
| October | 9.2 °C | 21.4 °C | 93.22 mm |
| November | 3.4 °C | 15.1 °C | 78.99 mm |
| December | -0.2 °C | 10.1 °C | 95.5 mm |
| Annual | 8.5 °C | 19.9 °C | 1147.3 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |