Merritt Island, Florida has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 19 °C (low) to 26.8 °C (high). Annual precipitation averages 1398.3 Millimeters. Merritt Island is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12 °C | 21 °C | 72.9 mm |
| February | 13.1 °C | 22.2 °C | 64.52 mm |
| March | 15.3 °C | 23.8 °C | 83.31 mm |
| April | 18.2 °C | 26.2 °C | 73.15 mm |
| May | 21.1 °C | 28.5 °C | 89.66 mm |
| June | 23.3 °C | 30.4 °C | 179.07 mm |
| July | 23.9 °C | 31.4 °C | 166.12 mm |
| August | 24.3 °C | 31.3 °C | 188.21 mm |
| September | 23.9 °C | 30.6 °C | 207.77 mm |
| October | 21.6 °C | 28.3 °C | 140.72 mm |
| November | 17.2 °C | 24.9 °C | 70.61 mm |
| December | 14 °C | 22.4 °C | 62.23 mm |
| Annual | 19 °C | 26.8 °C | 1398.27 mm |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |