Marathon, Florida has a Tropical Savanna (Wet and Dry Climate) climate (Köppen classification: Aw). Average annual temperatures range from 73.3 °F (low) to 82.7 °F (high). Annual precipitation averages 42.6 Inches. Marathon is located in USDA Plant Hardiness Zone 11b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 64.4 °F | 74.6 °F | 1.91 in. |
| February | 66.1 °F | 76.2 °F | 1.67 in. |
| March | 68.5 °F | 78.0 °F | 1.57 in. |
| April | 72.6 °F | 81.9 °F | 1.76 in. |
| May | 76.0 °F | 84.9 °F | 3.71 in. |
| June | 78.6 °F | 88.1 °F | 4.92 in. |
| July | 79.8 °F | 89.6 °F | 4.2 in. |
| August | 80.0 °F | 89.9 °F | 6.32 in. |
| September | 78.7 °F | 88.4 °F | 6.7 in. |
| October | 76.3 °F | 84.7 °F | 5.86 in. |
| November | 71.3 °F | 79.5 °F | 2.08 in. |
| December | 67.6 °F | 76.6 °F | 1.9 in. |
| Annual | 73.3 °F | 82.7 °F | 42.6 in. |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 11b : 45°F to 40°F |
| Plant Hardiness Zone - 2012 | Zone 11b : 45°F to 40°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Aw - Tropical Savanna (Wet and Dry Climate) |