Garrison, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 5.8 °C (low) to 19.2 °C (high). Annual precipitation averages 1189.2 Millimeters. Garrison is located in USDA Plant Hardiness Zone 6b. 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 | -5.2 °C | 5.7 °C | 84.84 mm |
| February | -4.2 °C | 7.8 °C | 83.31 mm |
| March | -0.8 °C | 13.1 °C | 111.76 mm |
| April | 4.7 °C | 20.3 °C | 108.71 mm |
| May | 10.4 °C | 24.6 °C | 121.67 mm |
| June | 15.3 °C | 28.8 °C | 116.08 mm |
| July | 17.4 °C | 30.5 °C | 131.32 mm |
| August | 16.6 °C | 30.1 °C | 89.92 mm |
| September | 12.5 °C | 26.9 °C | 89.66 mm |
| October | 5.8 °C | 20.8 °C | 78.99 mm |
| November | -0.2 °C | 13.6 °C | 76.96 mm |
| December | -2.9 °C | 7.8 °C | 96.01 mm |
| Annual | 5.8 °C | 19.2 °C | 1189.23 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |