Guntersville, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.4 °C (low) to 22.1 °C (high). Annual precipitation averages 1413.8 Millimeters. Guntersville is located in USDA Plant Hardiness Zone 8a. 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 | -0.2 °C | 10.5 °C | 133.1 mm |
| February | 1.3 °C | 12.9 °C | 136.65 mm |
| March | 5.2 °C | 17.6 °C | 129.54 mm |
| April | 9.5 °C | 22.3 °C | 127.51 mm |
| May | 14.7 °C | 26.5 °C | 112.52 mm |
| June | 19.2 °C | 30.2 °C | 121.41 mm |
| July | 21.1 °C | 31.7 °C | 100.58 mm |
| August | 20.6 °C | 31.7 °C | 97.54 mm |
| September | 17.2 °C | 29 °C | 103.63 mm |
| October | 10.6 °C | 23.3 °C | 94.23 mm |
| November | 4.4 °C | 16.8 °C | 115.06 mm |
| December | 1.4 °C | 12.1 °C | 141.99 mm |
| Annual | 10.4 °C | 22.1 °C | 1413.76 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |