Marathon, Florida Keys weather in July
Temperature, sea and sunshine in July: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in July
Excellent
Best time to visit: March – May, July, November – December
What is the weather like in Marathon, Florida Keys in July?
In July, Marathon, Florida Keys is hot: daytime highs average 29 °C, and even at night it stays warm at around 27 °C. The sea averages 29.7 °C – almost as warm as a bath. The sun shines for around 9 hours a day. It rains often – on about 14 days, adding up to 74 mm. The air is often humid and muggy. All in all, July is an excellent month for a holiday in Marathon, Florida Keys.
July compared
How the weather changes from June to August. Tap a month to open it.
More details for July
- Daylight
- 13 h 32 min06:44 – 20:16
- UV index
- 12 · extremeclear sky, noon (estimate)All months
- Muggy days
- 31 daysdew point 18 °C or moreAll months
- Wind
- 22 km/haverage daily peakAll months
- Cloud cover
- 60 %on averageAll months
- Hot days
- 2 days30 °C or moreAll months
- Time zone
- UTC−4America/New_York
How the score comes together
- Temperatureweight 35 %100 %
- Seaweight 25 %100 %
- Sunshineweight 20 %95 %
- Few rainy daysweight 20 %29 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in July
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Marathon, Florida Keys in July: quick answers
Is Marathon, Florida Keys hot in July?
Yes. In July, Marathon, Florida Keys is hot: daytime highs average 29 °C and nights stay around 27 °C. On about 2 days the thermometer climbs to 30 °C or more.
Can you swim in Marathon, Florida Keys in July?
Yes. In July the sea averages 29.7 °C – almost as warm as a bath.
Does it rain much in Marathon, Florida Keys in July?
It rains often – on about 14 days, adding up to 74 mm.
Marathon, Florida Keys month by month
The whole year in Marathon, Florida KeysAll destinations: USAFlorida weather in JulyWhere to go in JulySea temperature in July
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences