Key West, Florida has a Tropical Savanna (Wet and Dry Climate) climate (Köppen classification: Aw). Average annual temperatures range from 22.9 °C (low) to 28.4 °C (high). Annual precipitation averages 1098.6 Millimeters. Key West is located in USDA Plant Hardiness Zone 11b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18 °C | 23.7 °C | 43.43 mm |
| February | 18.9 °C | 24.7 °C | 52.32 mm |
| March | 20.2 °C | 25.8 °C | 38.86 mm |
| April | 22.4 °C | 28 °C | 57.4 mm |
| May | 24.3 °C | 29.7 °C | 78.49 mm |
| June | 25.9 °C | 31.3 °C | 119.38 mm |
| July | 26.5 °C | 32.3 °C | 105.16 mm |
| August | 26.6 °C | 32.2 °C | 139.45 mm |
| September | 25.9 °C | 31.4 °C | 183.9 mm |
| October | 24.6 °C | 29.6 °C | 166.37 mm |
| November | 21.8 °C | 26.7 °C | 62.23 mm |
| December | 19.8 °C | 24.9 °C | 51.56 mm |
| Annual | 22.9 °C | 28.4 °C | 1098.55 mm |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 11b : 7.2°C to 10°C |
| Plant Hardiness Zone - 2012 | Zone 11b : 7.2°C to 10°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Aw - Tropical Savanna (Wet and Dry Climate) |